9.10. Biokimia Lipid Bu Ina

7/23/2019 9.10. Biokimia Lipid Bu Ina

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CHEMISTRY OF LIPIDSCHEMISTRY OF LIPIDS

Defnition:

Lipids are organic compounds

ormed mainly rom alcohol andatty acids combined together byester linkage.

CH2

R

Fatty alcoholOH C R

Fatty acidHO

O

+H2O

CH2

R O C R

O

Esterase (lipase) ester (lipid)


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Lipids are insoluble in water,

but soluble in at or organicsolvents (ether, chloroorm,benzene, acetone.

Lipids include ats, oils, wa!esand related compounds.

"hey are widely distributed in

nature both in plants and inanimals.


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#iological $mportance o Lipids:1. They are more palatable and storable to

unlimited amount compared to carbohydrates.

2. They have a high-energy value (25% of bodyneeds) and they provide more energy per gramthan carbohydrates and proteins butcarbohydrates are the preferable source ofenergy.

. !upply the essential fatty acids that cannot besynthesi"ed by the body.

#. !upply the body $ith fat-soluble vitamins (& '& and ).

5. They are important constituents of the nervoussystem.

*. Tissue fat is an essential constituent of cellmembrane and nervous system. +t is mainlyphospholipids in nature that are not a,ected bystarvation.


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#iological $mportance o Lipids:...............cont

%&'tored lipidsdepot at) is stored in all humancells acts as:

* store o energy. * pad or the internal organs to protect them

rom outside shocks. * subcutaneous thermal insulator against loss o

body heat.+&Lipoproteins, which are comple! o lipids and

proteins, are important cellular constituentsthat present both in the cellular and subcellularmembranes.

&-holesterolenters in membrane structure and is

used or synthesis o adrenal cortical hormones,vitamin D and bile acids./0& Lipidsprovide bases or dealing with diseases

such as obesity, atherosclerosis, lipid&storagediseases, essential atty acid defciency,respiratory distress syndrome&


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1iemann&2ick disease: in children

+t is one of lipid storage disease in $hich harmful

uantities of fatty substances& or lipids& accumulatein the spleen& liver& lungs& bone marro$& and brain

/iemann-0ic disease results from genetic absence

of sphingomyelinase en"yme leading toaccumulation of sphingomyelin in liver and spleenleading to enlargement of these organs and may

cause reduced appetite& abdominal distension andpain& and the enlarged spleen may trap platelets

and other blood cells& leading to reduced numbersof these cells in the circulation. The disease is fatalin early life.

!phingomyelin accumulation in the brain results inunsteady gait (ataia)& slurring of speech and

di3cult s$allo$ing (dysphagia). 4ore $idespreaddisease involving the cerebral crortecause dementia and sei"ers.


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/. 'imple lipids (3ats , oil 45a!es

ester asam lema dengan

berbagai alohol6 -ompound or con7ugated lipids ester asam lema mengandung

gugus selain asam lema alohol. Derived Lipids8. Lipid&associating substances


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/&9lycerol: $t is a trihydric alcohol (i.e.,

containing three ; groups andhas the popular name glycerin.

$t is synthesized in the body romglucose.

$t has the ollowing properties:

CH2

R

Fatty alcoholOH C R

Fatty acidHO

O

+H2O

CH2

R O C R

O



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/. -olorless viscous oily li


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&$t combines with three molecules onitric acid to orm trinitroglycerinthat is used as vasodilator.

8&n esterifcation with atty acids itgives:

>onoglyceride or monoacyl&glycerol:

one atty acid ? glycerol. Diglyceride or diacyl&glycerol: two

atty acids ? glycerol.

"riglyceride or triacyl&glycerol: threeatty acids ? glycerol.

@&$t has a nutritive value by conversioninto glucose and enters in structure

o phospholipids.


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Ases o 9lycerolAses o 9lycerol::

/. 9lycerol enters in pharmaceutical

and cosmetic preparations.6. Beduces brain edema in

cerebrovascular disease.

. 1itroglycerin is used as vasodilatorespecially or the coronary arteries,thus it is used in treatment oangina pectoris.

8. 9lycerol is used in treatment oglaucoma(increased intraocularpressuredue to its ability todehydrate the tissue rom its water

content.


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6&'phingosine:6&'phingosine:

& $t is the alcohol (monohydricpresent in sphingolipids.

& $t is synthesized in the bodyrom serine and palmitic acid.

$t is not positive with acroleintest.


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DefnitionDefnition: 3atty acids are aliphatic mono&

carbo!ylic acids that are mostlyobtained rom the hydrolysis o naturalats and oils.

;ave the general ormula B&(-;6n&-; andmostly have straight chain(a ew e!ceptions have branched andheterocyclic chains. $n this ormula

CnC is mostly an even number o carbonatoms (6&8 with a ew e!ceptionsthat have an odd number.

3atty acids are classifed according to

several bases as ollows:

CH2R

Fatty alcoholOH C R

Fatty acid

HO

O

+

H2O

CH2R O C R

O



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$. *ccording to presence or absenceo double bonds they are classifed

into: *&'aturated 3atty *cids

they contain no doublebonds with6&68 or more carbons.

"hey are solid at room temperaturee!cept i they are short chained.

"hey may be even or odd

numbered. "hey have the ollowing molecular

ormula, -n;6n?/-;.


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'aturated atty acids'aturated atty acids(nodouble

*&'hort chain 'aturated 3.*.*&'hort chain 'aturated 3.*. (6&/0(6&/0

carbon.carbon.

a-!hort chain !aturated volatile 6..(2-* carbon).

b- !hort chain !aturated non volatile6..(7-18 carbon).

#&Long chain 'aturated 3.*#&Long chain 'aturated 3.*.(more.(morethe/0 carbonthe/0 carbon


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a&olatile short&chain atty acids:

"hey are li


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b&1on&volatile short&chain attyb&1on&volatile short&chain attyacidsacids:

"hey are solids at room"hey are solids at roomtemperature and containtemperature and contain %&/0%&/0carbon atoms.carbon atoms.

"hey are water&soluble and non&"hey are water&soluble and non&volatile at room temperaturevolatile at room temperatureinclude caprylic and capric 3.*.include caprylic and capric 3.*.

caprylic (+ - -;caprylic (+ - -;&(-;&(-;66EE&-;.&-;.

-apric (/0 - -;-apric (/0 - -;&(-;&(-;66++&&

-;.-;.


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#&Long&chain atty acids: "hey contain more than /0 carbon atoms.

"hey occur in hydrogenated oils, animal ats,butter and coconut and palm oils.

"hey are non&volatile and water&insoluble

$nclude palmitic, stearic, and lignoceric 3.*.

palmitic(/E- -;palmitic(/E- -;&(-;&(-;66/8/8&-;&-;

stearic (/+ - -;stearic (/+ - -;&(-;&(-;66/E/E&-;&-;

lignoceric (68- -;lignoceric (68- -;&(-;&(-;666666&-;&-;


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#&Ansaturated 3atty *cids

"hey contain doublebond monounsaturated

they contain one double bonds .

(-n;6n&/-;

polyunsaturated

they contain more the one doublebond (-n;6n&morethan /-;.


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1-4onounsaturated fatty acids:

/&2almitoleic acid :

$t is ound in all ats.

$t is -/E:/F, i.e., has /Ecarbons and one double bondlocated at carbon number andinvolving carbon /0.

-;-;..&( -;&( -;66@@-; G -;&(-;-; G -;&(-;66%% HH

-;-;


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6&leic acid

$s the most common atty acid in$s the most common atty acid in

natural ats.natural ats.

$t is$t is -/+:/F-/+:/F, i.e., has /+ carbons, i.e., has /+ carbons

and one double bond located atand one double bond located at

carbon number and involvingcarbon number and involving

carbon /0.carbon /0.

-;-;..&(-;&(-;66%%& -;G-; H (-;& -;G-; H (-;66%%&-;&-;


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&1ervonic acid

(Ansaturated lignoceric acid.

$t is ound in cerebrosides.

$t is -68://@, i.e., has 68

carbons and one double bondlocated at carbon number /@and involving carbon /E.

-;-;..H (-;H (-;66%%-;G -; H (-;-;G -; H (-;66/./.&&

-;-;


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6&2olyunsaturated atty acids:

(Issential atty acids: Defnition:

"hey are essential atty acids

that can not be synthesizedinthe human body and must betaken in ade


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'ource:vegetable oils such as cornoil, linseed oil, peanut oil, olive oil,

cottonseed oil, soybean oil andmany other plant oils, cod liver oiland animal ats.

Defciency:"heir defciency in the

diet leads to nutrition defciencydisease.

$ts symptomsinclude: poor growthand health with susceptibility to

inections, dermatitis, decreasedcapacity to reproduce, impairedtransport o lipids, atty liver, andlowered resistance to stress.


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3unction o Issential 3atty *cids:

/. "hey are useul in the treatment oatherosclerosisby help transporting blood

cholesterol and lowering it and transportingtriglycerides.

6. "he hormones are synthesized rom them.

. "hey enter in structure o all cellular andsubcellular membranes and the transporting

plasma phospholipids.8. "hey are essential or skin integrity, normal

growthand reproduction.

@. "hey have an important role in blood clotting(intrinsic actor.

E. $mportant in preventing and treating attyliver.

%. $mportant role in health o the retina andvision.

+. "hey can be o!idized or energy production.


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/&Linoleic:/&Linoleic:

-/+:6, /6. in corn, linseed, peanut, olive,

cottonseed and soybean oils.

-;-;..&(-;&(-;6688&-; G -;&-;&-; G -;&-;66&-;G-;&&-;G-;&

(-;(-;66%%&-;&-;


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6&Linolenic acid6&Linolenic acid:

-/+:, /6, /@, 'ome plants e.g. evening

primrose oilJ borage oilJ minoratty acid in animal

-;-;..&-;&-;66&-;G-;&-;&-;G-;&-;66&-;G-;&&-;G-;&

-;-;66&-;G-;&(-;&-;G-;&(-;66%%&-;&-;


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&*rachidonic acid&*rachidonic acid:

-60:8@, +, //, /8.

$t is an important component ophospholipids in animal and inpeanut oil rom which

prostaglandins are synthesized.

-;-;..&(-;&(-;6688&-;G-;&-;&-;G-;&-;66&-;G-;&-;&-;G-;&-;66&&

-;G-;&-;-;G-;&-;66&-;G-;&(-;&-;G-;&(-;66..&-;&-;


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/&'imple Lipids*&1eutral 3ats and oils*&1eutral 3ats and oils

("riglycerides("riglyceridesDefnition:Defnition: & "hey are called neutral because& "hey are called neutral because

they are uncharged due to absencethey are uncharged due to absence

o ionizable groups in it.o ionizable groups in it. "he neutral ats are the most"he neutral ats are the most

abundant lipids in nature. "heyabundant lipids in nature. "heyconstitute about +K o the lipidsconstitute about +K o the lipidso adipose tissue, 0K o plasma oro adipose tissue, 0K o plasma orliver lipids, less than /0K oliver lipids, less than /0K oerythrocyte lipids.erythrocyte lipids.

!i l li id t


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"hey are esters o glycerol with"hey are esters o glycerol with

various atty acids. 'ince the various atty acids. 'ince the hydro!yl groups o glycerol arehydro!yl groups o glycerol areesterifed, the neutral ats are alsoesterifed, the neutral ats are alsocalledcalled "riglycerides)."riglycerides).

Isterifcation o glycerol with oneIsterifcation o glycerol with onemolecule o atty acid givesmolecule o atty acid givesmonoglyceridemonoglyceride, and that with 6, and that with 6molecules givesmolecules gives diglyceridediglyceride..

H2C O

C HO

H2C

C

C

O C

R1

R3

R2

O

O

O

+

3 H2O

CH2

OH

C HHO

CH2

OH

HO C R1

O

HO C R3

O

HO C R2

O

Fatty acids GlycerolTriglycerides

(Triacylglycerol)

!imple lipid..cont

!i l li id t


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"2I' 3 "B$9L-IB$DI'"2I' 3 "B$9L-IB$DI'

/&'imple triglycerides/&'imple triglycerides: $ the three atty: $ the three attyacids connected to glycerol are o theacids connected to glycerol are o the

same type the triglyceride is calledsame type the triglyceride is called

simple triglyceride, e.g., tripalmitin.simple triglyceride, e.g., tripalmitin.

6&>i!ed triglycerides6&>i!ed triglycerides: i they are o: i they are odiMerent types, it is called mi!eddiMerent types, it is called mi!ed

triglycerides, e.g., stearo&diolein andtriglycerides, e.g., stearo&diolein and

palmito&oleo&stearin.palmito&oleo&stearin.

1atural ats are mi!tures o mi!ed1atural ats are mi!tures o mi!ed

triglycerides with a small amount otriglycerides with a small amount o

simple triglycerides.simple triglycerides.

!imple lipid..cont

O


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CH2 O

C HO

CH2

C

C

O C

(CH2)14

O

O

O

Tripalitin(siple triacylglycerol)

CH3

(CH2)14CH3

(CH2

)14

CH3

CH2 O

C HO

CH2

C

C

O C

(CH2)16

O

O

O

!"Stearo"2,3"diolein(i#ed triacylglycerol)

CH3

(CH2)7CHCH(CH2)7CH3

(CH2)7 CH CH (CH2)7 CH3

CH2 O

C HO

CH2

C

C

O C

(CH2)14

O

O

O

!"palito"2"oleo"3"stearin

(i#ed triacylglycerol)

CH3

(CH2)16 CH3

(CH2)7CHCH(CH2)7CH3


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"he commonest atty acids in"he commonest atty acids inanimal ats areanimal ats are palmitic,palmitic,stearic and oleic acids.stearic and oleic acids.

"he main diMerence between"he main diMerence betweenats and oils is orats and oils is or oils beingoils being

li


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2hysical properties o at and oils:2hysical properties o at and oils:/. 3reshly prepared ats and oils are

colorless, odorless and tasteless. *nycolor, or taste is due to association withother oreign substances, e.g., theyellow color o body at or milk at is dueto carotene pigments(cow milk.

6. 3ats have specifc gravity less than /and, thereore, they Noat on water.

. 3ats are insoluble in water, but soluble inorganic solvents as ether and benzene.

8. >elting points o ats are usuallylow, but higher than thesolidifcation point,


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-hemical 2roperties o ats and-hemical 2roperties o ats andoilsoils:

/&;ydrolysis:/&;ydrolysis: "hey are hydrolyzed into their constituents"hey are hydrolyzed into their constituents

((atty acids and glycerolatty acids and glycerolby the action oby the action o

super heated steam, acid, alkali or enzymesuper heated steam, acid, alkali or enzyme

(e.g., lipase o pancreas.(e.g., lipase o pancreas. & During their enzymatic and acid hydrolysis& During their enzymatic and acid hydrolysis

glycerol and ree atty acids are produced.glycerol and ree atty acids are produced.

CH2O

C HO

CH2

C

C

O C

R1

R3

R2

O

O

O

3 H2O

H2C OH

C HHO

H2C OH

OHCR1

O

OHCR3

O

+ OHCR2

OLipase or Acid

Triacylglycerol Glycerol Free $atty acids


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6&'aponifcation.*lkaline hydrolysis*lkaline hydrolysisproduces glycerol and salts o attyproduces glycerol and salts o attyacids (acids (soapssoaps..

'oaps cause emulsifcation o oily'oaps cause emulsifcation o oilymaterial this help easy washing o thematerial this help easy washing o theatty materialsatty materials

CH2O

C HO

CH2

C

C

O C

R1

R3

R2

O

O

O

H2C OH

C HHO

H2C OH

ONaCR1

O

ONaCR3

O

+ ONaCR2

O

Triacylglycerol Glycerol Sodi% salts o$$atty acids (soap)

3 NaOH


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&;alogenation&;alogenation 1eutral ats containing unsaturated atty1eutral ats containing unsaturated atty

acids have the ability o adding halogensacids have the ability o adding halogens

(e.g., hydrogen or hydrogenation and iodine(e.g., hydrogen or hydrogenation and iodineor iodination at the double bonds.or iodination at the double bonds.

& $t is a very important property to& $t is a very important property to

determine the degree o unsaturation o thedetermine the degree o unsaturation o the

at or oil that determines its biologicalat or oil that determines its biologicalvaluevalue

CH (CH2)7 COOHCHCH2CH

&inoleic acid

CH(CH2)4CH3

2 '2

CH (CH2)7 COOHCHCH2CH

Stearate"tetra"iodinate

CH(CH2)4CH3

II I I


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8&;ydrogenation or hardening o oils8&;ydrogenation or hardening o oils: $t is a type o addition reactions$t is a type o addition reactions

accepting hydrogen at the double bondsaccepting hydrogen at the double bonds

o unsaturated atty acids.o unsaturated atty acids. "he hydrogenation is done under high"he hydrogenation is done under high

pressure o hydrogen and is catalyzed bypressure o hydrogen and is catalyzed byfnely divided nickel or copper and heat.fnely divided nickel or copper and heat.

$t is the base o hardening o oils$t is the base o hardening o oils((margarine manuacturingmargarine manuacturing, e.g., change, e.g., changeo oleic acid o ats (li


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Oils(li%id)

(ith %nsat%rated$atty acids, e*g*, oleic)

Hard $at(argarine, solid)(ith sat%rated

$atty acids, e*g*, stearic)

Hydrogen, high pressure, nickel

*dvantages or hydrogenatedoil or at are asollows:

/./. $t is more pleasant as cooking at.$t is more pleasant as cooking at.

6.6. $t is digestible and utilizable as normal$t is digestible and utilizable as normalanimal ats and oils.animal ats and oils.

.. $t is less liable to cause gastric or intestinal$t is less liable to cause gastric or intestinalirritation.irritation.

8.8. $t is easily stored and transported and less$t is easily stored and transported and less

liable to rancidity.liable to rancidity.'isadvantages of hydrogenated'isadvantages of hydrogenated ats include lack o at&soluble vitamins (*,ats include lack o at&soluble vitamins (*,

D, I and = and essential atty acidsD, I and = and essential atty acids


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@&!idation(Bancidty@&!idation(Bancidty

"his to!icreaction o triglyceridesleads to unpleasant odour or tasteo oils and ats developing atero!idation by o!ygen o air, bacteria,

or moisture. *lso this is the base o the drying

oils ater e!posure to atmospherico!ygen.

I!ample is linseed oil, which is usedin paints and varnishesmanuacturing


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BancidityBancidityDefnition:Defnition: $t is a physico&chemical change in$t is a physico&chemical change in

the natural properties o the atthe natural properties o the atleading to the development oleading to the development ounpleasant odor or taste orunpleasant odor or taste orabnormal colorabnormal colorparticularly onparticularly onaging ater e!posure toaging ater e!posure toatmospheric o!ygen, light,atmospheric o!ygen, light,moisture, bacterial or ungalmoisture, bacterial or ungalcontamination andPor heat.contamination andPor heat.

'aturated ats resist rancidity'aturated ats resist ranciditymore than unsaturated ats thatmore than unsaturated ats that

have unsaturated double bonds.have unsaturated double bonds.


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"ypes and causes o Bancidity"ypes and causes o Bancidity:/./. ;ydrolytic rancidity;ydrolytic rancidity

6.6. !idative rancidity!idative rancidity.. =etonic rancidity=etonic rancidity

/&;ydrolytic rancidity/&;ydrolytic rancidity: $t results rom slight hydrolysis o$t results rom slight hydrolysis o

the at by lipase rom bacterialthe at by lipase rom bacterialcontamination leading to thecontamination leading to theliberation o ree atty acids andliberation o ree atty acids and

glycerol at high temperature andglycerol at high temperature andmoisture.moisture.

olatile short&chain atty acids haveolatile short&chain atty acids haveunpleasant odor.unpleasant odor.


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CH2O

C HO

CH2

C

C

O C

R1

R3

R2

O

O

O

3 H2O

H2C OH

C HHO

H2C OH

OHCR1

O

OHCR3

O

+ OHCR2

OLipase

Triacylglycerol Glycerol Free $atty acids(olatile, ad odor)


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6&!idative Bancidity6&!idative Bancidity:

$t is o!idation o at or oil catalyzed$t is o!idation o at or oil catalyzedby e!posure to o!ygen, light andPorby e!posure to o!ygen, light andPorheat producing pero!ide derivativesheat producing pero!ide derivativeswhich on decomposition givewhich on decomposition give

substances, e.g.,substances, e.g., pero!ides,pero!ides,aldehydes, ketones and dicarbo!ylicaldehydes, ketones and dicarbo!ylicacids that are to!ic and have badacids that are to!ic and have badodor.odor.

"his occurs due to o!idative addition"his occurs due to o!idative additiono o!ygen at the unsaturated doubleo o!ygen at the unsaturated doublebond o unsaturated atty acid obond o unsaturated atty acid ooils.oils.


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-oly%nsat%rated $atty acid

-ero#yradical

Oxidant, O2

Hydropero#ide

Hydro#y $atty acid

.yclic pero#ide

Aldehydess%ch as alondialdehyde

Other $ragentss%ch as dicar,o#ylic acids


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&=etonic Bancidity:

$t is due to the contamination$t is due to the contaminationwith certain ungi such aswith certain ungi such as

*sperigillus 1iger on ats such as*sperigillus 1iger on ats such as

coconut oil.coconut oil.

=etones, atty aldehydes, short=etones, atty aldehydes, short

chain atty acids and attychain atty acids and atty

alcohols are ormed.alcohols are ormed.

>oisture accelerates ketonic>oisture accelerates ketonicrancidity.rancidity.


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2revention o rancidity is2revention o rancidity isachieved by:achieved by:

/./. *voidance o the causes (*voidance o the causes (e!posure toe!posure tolight, o!ygen, moisture, highlight, o!ygen, moisture, hightemperature and bacteria or ungaltemperature and bacteria or ungalcontaminationcontamination. #y keeping ats or oils. #y keeping ats or oilsin well&closed containers in cold, darkin well&closed containers in cold, dark

and dry place (i.e.,and dry place (i.e., good storagegood storageconditions.conditions.6.6. Bemoval o catalysts such as lead andBemoval o catalysts such as lead and

copper that catalyze rancidity.copper that catalyze rancidity... *ddition o*ddition o anti&o!idantsanti&o!idantsto preventto prevent

pero!idation in at (i.e., rancidity.pero!idation in at (i.e., rancidity."hey include phenols, naphthols,"hey include phenols, naphthols,tannins and hydro


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;azards o Bancid 3ats:

/./. "he products o rancidity are"he products o rancidity are

to!ic, i.e., causes ood poisoningto!ic, i.e., causes ood poisoningand cancer.and cancer.

6.6. Bancidity destroys the at&solubleBancidity destroys the at&soluble

vitamins (vitamins *, D, = and I.vitamins (vitamins *, D, = and I... Bancidity destroys theBancidity destroys the

polyunsaturated essential attypolyunsaturated essential atty

acids.acids.

8.8. Bancidity causes economical lossBancidity causes economical lossbecause rancid at is inedible.because rancid at is inedible.


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*nalysis and $dentifcation o ats and*nalysis and $dentifcation o ats andoilsoils

(3at -onstants(3at -onstants 3at constants or numbers are tests3at constants or numbers are tests

used or:used or:

/./. -hecking the purity o at or-hecking the purity o at or

detection o adulteration.detection o adulteration.

6.6. "o


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/&$odine number/&$odine number(or value): 'e9nition: $t is the number o grams

oiodineabsorbed by /00 gramsoat or oil.

ses: $t is a measure or the degree ounsaturation o the at, as a natural

property or it. Ansaturated atty acids absorb iodine at

their double bonds, thereore, as thedegree o unsaturation increases iodine

numberand hence biological value othe at increase. $t is used or identifcation o the type o

at, detection o adulterationanddetermining the biological value o at.


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6&'aponifcation number(or value): DefnitionDefnition: $t is the number o$t is the number o

milligrams omilligrams o=;=;re


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&*cids 1umber&*cids 1umber(or value):

DefnitionDefnition::

$t is the number o$t is the number o milligrams omilligrams o=;=;re


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8&Beichert& >eissl 1umber8&Beichert& >eissl 1umber(or value):

DefnitionDefnition: $t is the number o: $t is the number o millilitersmillilitersoo0./ 10./ 1 =;=;reeissl number compared to

margarine.margarine.

@ * l 1 b ( l )


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@&*cetyl 1umber@&*cetyl 1umber(or value): DefnitionDefnition: $t is number o$t is number o milligramsmilligrams

oo=;=; needed to neutralize the aceticneeded to neutralize the acetic

acid liberated rom hydrolysis oacid liberated rom hydrolysis o //gram o acetylated atgram o acetylated at(hydro!y at(hydro!y atreacted with acetic anhydridereacted with acetic anhydride).

Ases:Ases:"he natural or rancid at that"he natural or rancid at that

contains atty acids with ree hydro!ylcontains atty acids with ree hydro!ylgroups are converted into acetylatedgroups are converted into acetylatedat by reaction with acetic anhydride.at by reaction with acetic anhydride.

"hus, acetyl number is a measure o"hus, acetyl number is a measure o

number o hydro!yl groups present.number o hydro!yl groups present. $t is used or studying the natural$t is used or studying the natural

properties o the at and to detectproperties o the at and to detectadulterationadulteration and rancidity.and rancidity.

#&5a!es#&5a!es


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# 5a!es DefnitionDefnition: 5a!es are solid simple lipids5a!es are solid simple lipids

containing a monohydric alcohol (with acontaining a monohydric alcohol (with a

higher molecular weight than glycerolhigher molecular weight than glycerolesterifed to long&chain atty acids.esterifed to long&chain atty acids.I!amples o these alcohols areI!amples o these alcohols are palmitoylpalmitoylalcohol, cholesterol, vitamin * or D.alcohol, cholesterol, vitamin * or D.

2roperties o wa!es2roperties o wa!es: 5a!es are: 5a!es areinsoluble in water, but soluble in atinsoluble in water, but soluble in at

solvents and are negative or acroleinsolvents and are negative or acroleintest.test.

5a!es are not easily hydrolyzed as the5a!es are not easily hydrolyzed as theats and are indigestible by lipases andats and are indigestible by lipases andare very resistant to rancidity.are very resistant to rancidity.

"hus they are o no nutritional value."hus they are o no nutritional value.

" 5"

5


57/94

"ype o 5a!es"ype o 5a!es:

- ;aes are $idely distributed in naturesuch as the secretion of certain insects asbees-$a& protective coatings of the sinsand furs of animals and leaves and fruitsof plants. They are classi9ed into true-

$aes and $a-lie compounds as follo$s:*&"rue wa!es*&"rue wa!es: include:

#ees&wa!#ees&wa!is secreted by the honeybeesthat use it to form the combs. +t is a

miture of $aes $ith the chiefconstituent is mericyl palmitate.


58/94

C15H31 C OH

O

+C30H61OH C15H31 C OO

C30H61

H2O-alitic

acid/ericylalcohol

/ericylpalitate

#&5a!&like compounds:

-holesterol esters-holesterol esters: Lanolin (or woolLanolin (or wool

at is prepared rom the wool&at is prepared rom the wool&associated skin glands and is secretedassociated skin glands and is secretedby sebaceous glands o the skin.by sebaceous glands o the skin.

$t is very comple! mi!ture, contains$t is very comple! mi!ture, containsboth ree and esterifed cholesterol,both ree and esterifed cholesterol,e.g., cholesterol&palmitate and othere.g., cholesterol&palmitate and othersterolssterols.

Differences between neutra i!i"s an" wa#es


59/94

Differences between neutra i!i"s an" wa#es$

Waxes Neutral lipidsNeutral lipids

1.1.Digestibility:Digestibility: Indigestible (notIndigestible (nothydrolyzed by lipase).hydrolyzed by lipase).

Digestible (hydrolyzed by lipase).Digestible (hydrolyzed by lipase).

2-Type o2-Type o

al!oholal!ohol::

"ong-!hain #onohydri!"ong-!hain #onohydri!

al!ohol $ one atty a!id.al!ohol $ one atty a!id.%ly!erol (trihydri!) $ & atty a!ids%ly!erol (trihydri!) $ & atty a!ids

&-Type o atty&-Type o atty

a!idsa!ids::

'atty a!id #ainly pal#iti!'atty a!id #ainly pal#iti!

or steari! a!id.or steari! a!id.

"ong and short !hain atty a!ids."ong and short !hain atty a!ids.

-!rolein test-!rolein test: Negati*e.Negati*e. +ositi*e.+ositi*e.

,-an!idability:,-an!idability: Ne*er get ran!id.Ne*er get ran!id. an!idible.an!idible.

-Nature at-Nature at

roo#roo#te#peraturete#perature.

/ard solid./ard solid. 0ot solid or liuid.0ot solid or liuid.

-0aponii!ation-0aponii!ation Nonsaponiiable.Nonsaponiiable. 0aponiiable.0aponiiable.

3-Nutriti*e3-Nutriti*e

*alue*alue:

No nutriti*e *alue.No nutriti*e *alue. Nutriti*e.Nutriti*e.

4-5xa#ple:4-5xa#ple: 6ee 7 !arnuba 8axes.6ee 7 !arnuba 8axes. 6utter and *egetable oils.6utter and *egetable oils.


60/94

6&-ompound Lipids6&-ompound LipidsDefnitionDefnition:

"hey are lipids that contain additional"hey are lipids that contain additionalsubstances, e.g., sulur, phosphorus,substances, e.g., sulur, phosphorus,amino group, carbohydrate, oramino group, carbohydrate, orproteins beside atty acid and alcohol.proteins beside atty acid and alcohol.

-ompound or con7ugated lipids are-ompound or con7ugated lipids are

classifed into the ollowing typesclassifed into the ollowing typesaccording to the nature o theaccording to the nature o theadditional group:additional group:

/./. 2hospholipids2hospholipids

6.6. 9lycolipids.9lycolipids... LipoproteinsLipoproteins8.8. 'ulolipids and amino lipids.'ulolipids and amino lipids.

* 2hospholipids* 2hos

pholipids


61/94

*&2hospholipids*&2hospholipidsDefnition:Defnition:2hospholipids or phosphatides are2hospholipids or phosphatides are

compound lipids, which contain phosphoric acidcompound lipids, which contain phosphoric acidgroup in their structuregroup in their structure..

$mportance$mportance:/./. "hey are present in large amounts in the liver"hey are present in large amounts in the liver

and brain as well as blood. Ivery animal andand brain as well as blood. Ivery animal andplant cell contains phospholipids.plant cell contains phospholipids.

6.6. "he membranes bounding cells and subcellular"he membranes bounding cells and subcellular

organelles are composed mainly oorganelles are composed mainly ophospholipids. "hus, the transer o substancesphospholipids. "hus, the transer o substancesthrough these membranes is controlled bythrough these membranes is controlled byproperties o phospholipids.properties o phospholipids.

.. "hey are important components o the"hey are important components o thelipoprotein coat essential or secretion andlipoprotein coat essential or secretion and

transport o plasma lipoprotein comple!es.transport o plasma lipoprotein comple!es."hus, they are lipotropic agents that"hus, they are lipotropic agents that preventpreventatty liveratty liver..

8.8. >yelin sheath o nerves is rich with>yelin sheath o nerves is rich withphospholipids.phospholipids.

@ $ t t i di ti d b ti @ $mportant in digestion and absorption o


62/94

@&$mportant in digestion and absorption o@&$mportant in digestion and absorption oneutral lipids and e!cretion oneutral lipids and e!cretion ocholesterol in the bile.cholesterol in the bile.

E&$mportant unction in blood clotting andE&$mportant unction in blood clotting andplatelet aggregation.platelet aggregation.

%&"hey provide lung alveoli with%&"hey provide lung alveoli withsuractants that prevent itssuractants that prevent itsirreversible collapseirreversible collapse..

+&$mportant role in signal transduction+&$mportant role in signal transductionacross the cell membrane.across the cell membrane.

&2hospholipase *6 in snake venom&2hospholipase *6 in snake venomhydrolyses membrane phospholipidshydrolyses membrane phospholipidsinto hemolytic lysolecithin orinto hemolytic lysolecithin or

lysocephalin.lysocephalin./0&"hey are source o polyunsaturated/0&"hey are source o polyunsaturated

atty acids or synthesis oatty acids or synthesis o eicosanoids.eicosanoids.

' h d i ll ll


63/94

'ources:'ources:"hey are ound in all cells"hey are ound in all cells(plant and animal, milk and egg&(plant and animal, milk and egg&yolk in the orm o lecithins.yolk in the orm o lecithins.

'tructure'tructure: phospholipids are composedphospholipids are composedo:o:

/./. 3atty acids3atty acids(a saturated and an(a saturated and an

unsaturated atty acid.unsaturated atty acid.6.6. 1itrogenous base1itrogenous base(choline, serine,(choline, serine,

threonine, or ethanolamine.threonine, or ethanolamine.

.. 2hosphoric acid.2hosphoric acid.

8.8. 3atty alcohols3atty alcohols(glycerol, inositol(glycerol, inositolor sphingosine.or sphingosine.

-l if i 2h h li id


64/94

-lassifcation o 2hospholipids-lassifcation o 2hospholipidsareareclassifed into 6 groups according to theclassifed into 6 groups according to thetype o thetype o the alcoholalcoholpresent into twopresent into two

types:types:--9lycerophospholipids9lycerophospholipids:"hey are regarded as"hey are regarded as

derivatives o phosphatidic acids that are thederivatives o phosphatidic acids that are thesimplest type o phospholipids and include:simplest type o phospholipids and include:

/./.

2hosphatidic acids2hosphatidic acids

.

.

6.6. LecithinsLecithins

.. -ephalins-ephalins..

8.8. 2lasmalogens2lasmalogens..

@.@. $nositides$nositides..

E.E. -ardiolipin-ardiolipin.

#&'phingophospholipids#&'phingophospholipids:"hey contain"hey containsphingosine as an alcohol and are namedsphingosine as an alcohol and are named'phingomyelins'phingomyelins.

* 9l h h li id* 9l h h li id


65/94

*&9lycerophospholipids*&9lycerophospholipids/&2hosphatidic acids:/&2hosphatidic acids:"hey are metabolic"hey are metabolic

intermediates in synthesis o triglyceridesintermediates in synthesis o triglycerides

and glycerophospholipids in the body andand glycerophospholipids in the body andmay have unction as amay have unction as a second messengersecond messenger.."hey e!ist in two orms according to the"hey e!ist in two orms according to theposition o the phosphateposition o the phosphate

CH2 O

C HO

CH2

C

C

O %

R1

R2

O

O

"-hosphatidic acid

OH

OH

O

Saturatedatty acid!olyunsaturated

atty acid

!hosphate

CH2

O

C H

CH2

C

O

R1

O

"-hosphatidic acid

Saturatedatty acid

!olyunsaturatedatty acid

!hosphate %HOOH

O

C R2

O

O

6 Lecithins:6&Lecithins:


66/94

6&Lecithins:6&Lecithins: DefnitionDefnition: Lecithins areLecithins are

glycerophospholipids that contain cholineglycerophospholipids that contain choline

as a base beside phosphatidic acid. "heyas a base beside phosphatidic acid. "heye!ist in 6 ormse!ist in 6 orms & and& and

&lecithins.&lecithins.Lecithins are a common cell constituentLecithins are a common cell constituentobtained rom brain (obtained rom brain (

&type, egg yolk (&type, egg yolk (

&&type, or liver (both types. Lecithins aretype, or liver (both types. Lecithins are

important in the metabolism o at by theimportant in the metabolism o at by theliver.liver.

'tructure:'tructure:9lycerol is connected at -6 or -9lycerol is connected at -6 or -with a polyunsaturated atty acid, at -/with a polyunsaturated atty acid, at -/with a saturated atty acid, at - or -6 bywith a saturated atty acid, at - or -6 byphosphate to which the choline base isphosphate to which the choline base isconnected. "he common atty acids inconnected. "he common atty acids inlecithins are stearic, palmitic, oleic,lecithins are stearic, palmitic, oleic,linoleic, linolenic, clupandonic orlinoleic, linolenic, clupandonic or

arachidonic acids.arachidonic acids.

L l ithiL l ithi h l i B#- "hih l i B#- "hi


67/94

LysolecithinLysolecithincauses hemolysis o B#-s. "hiscauses hemolysis o B#-s. "hispartially e!plains to!ic the eMect o snakepartially e!plains to!ic the eMect o snakevenom,. "he venom containsvenom,. "he venom contains lecithinaselecithinase,,

which hydrolyzes the polyunsaturatedwhich hydrolyzes the polyunsaturatedatty converting lecithin into lysolecithin.atty converting lecithin into lysolecithin.Lysolecithins are intermediates inLysolecithins are intermediates in

metabolism o phospholipidsmetabolism o phospholipids.

CH2 O

C HO

CH2

C

C

O %

R1

R2

O

O

"&ecithin

O

OH

O

CH2 O

C H

CH2

C

O

R1

O

"&ecithin

%

OH

O

C R2

O

CH2

CH2

N

CH3

CH3

CH3

+

OCH2

CH2

N

CH3

CH3

CH3

+

.holine

.holine

O

L t tL

t t


68/94

Lung suractantLung suractant $s a comple! o dipalmitoyl&lecithin,$s a comple! o dipalmitoyl&lecithin,

sphingomyelin and a group o apoproteinssphingomyelin and a group o apoproteins

called apoprotein *, #, -, and D.called apoprotein *, #, -, and D. $t is produced by type $$ alveolar cells and$t is produced by type $$ alveolar cells and

is anchored to the alveolar surace o typeis anchored to the alveolar surace o type$$ and $ cells.$$ and $ cells.

$t lowers alveolar surace tension and$t lowers alveolar surace tension and

improves gas e!change besides activatingimproves gas e!change besides activatingmacrophages to kill pathogens.macrophages to kill pathogens. $n premature babies, this suractant is$n premature babies, this suractant is

defcient and they suMer romdefcient and they suMer rom respiratoryrespiratorydistress syndromedistress syndrome..

9lucocorticoids increase the synthesis o9lucocorticoids increase the synthesis othe suractant comple! and promotethe suractant comple! and promotediMerentiation o lung cells.diMerentiation o lung cells.

- h li ( = h li -

h li ( = h li


69/94

&-ephalins (or =ephalins:&-ephalins (or =ephalins:

DefnitionDefnition: "hey are phosphatidyl&"hey are phosphatidyl&

ethanolamine or serine. -ephalinsethanolamine or serine. -ephalinsoccur in association with lecithinsoccur in association with lecithinsin tissues and are isolated romin tissues and are isolated romthe brain (the brain (=ephale G head.=ephale G head.

'tructure'tructure: -ephalins resemble: -ephalins resemblelecithins in structure e!cept thatlecithins in structure e!cept thatcholine is replaced bycholine is replaced by

ethanolamine, serine or threonineethanolamine, serine or threonineamino acids.amino acids.

-ertain cephalins are constituents o the-ertain cephalins are constituents o the


70/94

-ertain cephalins are constituents o the-ertain cephalins are constituents o thecomple! mi!ture o phospholipids,comple! mi!ture o phospholipids,cholesterol and at that constitute the lipidcholesterol and at that constitute the lipid

component o the lipoproteincomponent o the lipoproteinthromboplastinthromboplastin) which accelerates the) which accelerates theclotting o blood by activation oclotting o blood by activation o

prothrombin to thrombin in presence oprothrombin to thrombin in presence ocalcium ionscalcium ions.

CH2 O

C HO

CH2

C

C

O %

R1

R2

O

O

".ephalin

O

OH

O

CH2 CH2 NH2 0thanolaine

HO CH2 CH COOH Serine

NH2

HO CH CH COOH Threonine

NH2CH3

8 2lasmalogens8 2lasmalogens:


71/94

8&2lasmalogens:8&2lasmalogens: Defnition:Defnition:2lasmalogens are ound in2lasmalogens are ound in

the cell membrane phospholipidsthe cell membrane phospholipids

raction o brain and muscle (/0K o itraction o brain and muscle (/0K o itis plasmalogens, liver, semen and eggs.is plasmalogens, liver, semen and eggs.

'tructure'tructure:2lasmalogens resemble2lasmalogens resemblelecithins and cephalins in structure butlecithins and cephalins in structure but

diMer in the presence odiMer in the presence o ,,&unsaturated&unsaturatedatty alcoholatty alcoholrather than a atty acid atrather than a atty acid at-/ o the glycerol connected by ether-/ o the glycerol connected by etherbond.bond.

*t -6 there is an unsaturated long&*t -6 there is an unsaturated long&chain atty acid, however, it may be achain atty acid, however, it may be avery short&chain atty acidvery short&chain atty acid


72/94

2roperties: 'imilar to lecithins'imilar to lecithins.

CH2

C HO

CH2

C

O %

R2

O

"-lasalogen

O

OH

O

CH2 CH2 N

CH3

CH3

CH3

+

"1nsat%rated$atty alcoholCH CH R1O

@ $ itid@ $nositides


73/94

@&$nositides@&$nositides: DefnitionDefnition::

- "hey are phosphatidyl inositol."hey are phosphatidyl inositol. 'tructure'tructure: "hey are similar to lecithins or"hey are similar to lecithins or

cephalins but they have the cyclic sugarcephalins but they have the cyclic sugaralcohol,alcohol, inositolinositol as the base. "hey areas the base. "hey are

ormed o glycerol, one saturated atty acid,ormed o glycerol, one saturated atty acid,one unsaturated atty acid, phosphoric acidone unsaturated atty acid, phosphoric acid

and inositoland inositol

CH2

C HO

CH2

C

O %

R2

O

"-hosphatidylinositol

O

OH

O

C R1O

O

H

H

OHOH

HOH

H

OHOH

H H!

2 3

4

'' # i i# i ti


74/94

'ource'ource: #rain tissues#rain tissues. 3unction3unction:

2hosphatidyl inositol is a ma7or2hosphatidyl inositol is a ma7orcomponent o cell membranecomponent o cell membranephospholipids particularly at thephospholipids particularly at theinner leaNet o it.inner leaNet o it.

"hey play a ma7or role as second"hey play a ma7or role as second

messengers during signalmessengers during signaltransduction or certain hormone..transduction or certain hormone..

n hydrolysis by phospholipase -,n hydrolysis by phospholipase -,phosphatidyl&inositol&8,@&diphosphatephosphatidyl&inositol&8,@&diphosphate

producesproduces

diacyl&glycerol and inositol&diacyl&glycerol and inositol&

triphosphatetriphosphateboth act to liberateboth act to liberatecalcium rom its intracellular stores tocalcium rom its intracellular stores tomediate the hormone eMects.mediate the hormone eMects.

E -ardiolipins:E -ardiolipins:


75/94

E&-ardiolipins:E&-ardiolipins:

DefnitionDefnition: "hey are diphosphatidyl&"hey are diphosphatidyl&

glycerol. "hey are ound in the innerglycerol. "hey are ound in the innermembrane o mitochondria initially isolatedmembrane o mitochondria initially isolated

rom heart muscle (cardio. $t is ormed o rom heart muscle (cardio. $t is ormed o molecules o glycerol, 8 atty acids and 6molecules o glycerol, 8 atty acids and 6

phosphate groupsphosphate groups

.

. 3unction3unction:: Ased in serological diagnosis oAsed in serological diagnosis o

autoimmunity diseases.autoimmunity diseases.

CH2

C HO

CH2

C

O %

R2

O

.ardiolipin

O

OH

O

C R1O

O

CH2

CH OH

CH2 CH2

CH O

CH2

C

O%

R3

O

O

OH

O

CR4 O

O

# 'phingophospholipids# 'phingophospholipids


76/94

#&'phingophospholipids#&'phingophospholipids/&'phingomyelins/&'phingomyelins Defnition:Defnition:'phingomyelins are ound in'phingomyelins are ound in

large amounts in brain and nerves and inlarge amounts in brain and nerves and insmaller amounts in lung, spleen, kidney,smaller amounts in lung, spleen, kidney,liver and bloodliver and blood.

'tructure:'tructure:'phingomyelins diMer rom'phingomyelins diMer romlecithins and cephalins in that they containlecithins and cephalins in that they containsphingosine as the alcohol instead osphingosine as the alcohol instead oglycerol, they contain two nitrogenousglycerol, they contain two nitrogenousbases: sphingosine itsel and choline.bases: sphingosine itsel and choline.

"hus, sphingomyelins contain sphingosine"hus, sphingomyelins contain sphingosinebase, one long&chain atty acid, choline andbase, one long&chain atty acid, choline andphosphoric acid.phosphoric acid.

"o the amino group o sphingosine the atty"o the amino group o sphingosine the attyacid is attached by an amide linkage.acid is attached by an amide linkage.

-eramide "his part o sphingomyelin in"his part o sphingomyelin in


77/94

-eramide"his part o sphingomyelin in"his part o sphingomyelin inwhich the amino group o sphingosine iswhich the amino group o sphingosine isattached to the atty acid by an amideattached to the atty acid by an amide

linkage.linkage. -eramides have been ound in the ree-eramides have been ound in the ree

state in the spleen, liver and red cells.state in the spleen, liver and red cells.

CH CH NH

CH2

CHCH(CH2)12CH3

OH

Sphingosine

C R1

O

O

% O

OH

O CH2 CH2 N

CH3

CH3

CH3

+

.holine

Fatty acid

-hosphate

.eraide

Sphingoyelin

#&9lycolipids#&9l

ycolipids


78/94

# 9lycolipids# 9lycolipids DefnitionDefnition: "hey are lipids that contain"hey are lipids that contain

carbohydrate residues with sphingosine ascarbohydrate residues with sphingosine as

the alcohol and a very long&chain atty acidthe alcohol and a very long&chain atty acid(68 carbon series.(68 carbon series.

"hey are present in cerebral tissue,"hey are present in cerebral tissue,

thereore are calledthereore are called cerebrosidescerebrosides

-lassifcation-lassifcation: *ccording to the number*ccording to the numberand nature o the carbohydrate residue(sand nature o the carbohydrate residue(spresent in the glycolipids the ollowing arepresent in the glycolipids the ollowing are

/. -erebrosides."hey have one galactose"hey have one galactosemolecule (galactosides.molecule (galactosides.

6. 'ulatides."hey are cerebrosides with"hey are cerebrosides withsulate on the sugar (sulated cerebrosides.sulate on the sugar (sulated cerebrosides.

. 9angliosides."hey have several sugar"hey have several sugarand sugaramine residues.and sugaramine residues.

/&-erebrosides:/&-erebrosides:


79/94

/ -erebrosides:/ -erebrosides: ccurrence: "hey occur in myelin sheath o nerves and

white matter o the brain tissues and cellularmembranes. "hey are important or nerve conductance.

'tructure: "hey contain sugar, usually &galactose and

may be glucose or lactose, sphingosine and atty acid,

but no phosphoric acid.

CH CH NH

CH2

CHCH(CH2)12CH3

OH

Sphingosine

C R1

O

O

-sychosin

Fatty acid

.eraide

.ere,roside

OOH

H HH

OHH

OH

CH2OH

HGalactose

"ypes"

ypes: *ccording to the type o atty*ccording to the type o atty


80/94

"ypes"ypes: *ccording to the type o atty*ccording to the type o attyacid and carbohydrate present, thereacid and carbohydrate present, thereare 8 diMerent types o cerebrosidesare 8 diMerent types o cerebrosides

isolated rom the white matter oisolated rom the white matter ocerebrum and in myelin sheaths ocerebrum and in myelin sheaths onerves. Babbit cerebrosides containnerves. Babbit cerebrosides containstearic acid.stearic acid.

/./. =erasin=erasincontains lignoceric acid (68contains lignoceric acid (68

carbons and galactose.carbons and galactose.6.6. -erebron (2hrenosin-erebron (2hrenosincontainscontains

cerebronic acid (6&hydro!ylignocericcerebronic acid (6&hydro!ylignocericacid and galactose.acid and galactose.

.. 1ervon1ervoncontains nervonic acidcontains nervonic acid(unsaturated lignoceric acid at -/@ and(unsaturated lignoceric acid at -/@ andgalactose.galactose.

8.8. !ynervon!ynervoncontains o!ynervonic acid (6&contains o!ynervonic acid (6&hydro!ynervonic acid and galactose.hydro!ynervonic acid and galactose.

6&'ulatides6&'ulatides:


81/94

6&'ulatides6&'ulatides: "hey are sulate esters o kerasin or"hey are sulate esters o kerasin or

phrenosin in which the sulate group isphrenosin in which the sulate group is

usually attached to the H; group o - orusually attached to the H; group o - or-E o galactose. 'ulatides are usually-E o galactose. 'ulatides are usuallypresent in the brain, liver, muscles andpresent in the brain, liver, muscles and

testes.testes.

CH CH NH

CH2

CHCH2(CH2)12CH3

OH

C R1

O

O

S%l$atides (s%l$ated cereroside)

OOH

H H

H

OHH

O&O3H

CH2OH

H

&9angliosides:&9angliosides:


82/94

&9angliosides: 9angliosides: "hey are more comple! glycolipids that"hey are more comple! glycolipids that

occur in the gray matter o the brain,occur in the gray matter o the brain,

ganglion cells, and B#-s. "hey transerganglion cells, and B#-s. "hey transerbiogenic amines across the cell membranebiogenic amines across the cell membraneand act as a cell membrane receptor.and act as a cell membrane receptor.

9angliosides9angliosidescontaincontain sialic acid (1&sialic acid (1&

acetylneuraminicacetylneuraminicacid,acid,ceramideceramide(sphingosine ? atty acid o /+&68 carbon(sphingosine ? atty acid o /+&68 carbon

atom length, molecules o he!oses (/atom length, molecules o he!oses (/glucose ? 6 galactose and he!osamine. "heglucose ? 6 galactose and he!osamine. "he

most simple type o it themost simple type o it the

monosialoganglioside,. $t works as amonosialoganglioside,. $t works as areceptor or cholera to!in in the humanreceptor or cholera to!in in the human

intestine.intestine.

.eraide"Gl%cose"Galactose"4"acetylgalactosaine"Galactose

/onosialoganglioside

Sialic acid

- Lipoproteins-&Li

poproteins


83/94

-&Lipoproteins-&Lipoproteins DefnitionDefnition:Lipoproteins are lipids combinedLipoproteins are lipids combined

with proteins in the tissues. "he lipidwith proteins in the tissues. "he lipid

component is phospholipid, cholesterol orcomponent is phospholipid, cholesterol ortriglycerides. "he holding bonds are secondarytriglycerides. "he holding bonds are secondarybonds.bonds.

"hey include:"hey include:/./. 'tructural lipoproteins'tructural lipoproteins: "hese are widely: "hese are widely

distributed in tissues being present in cellulardistributed in tissues being present in cellular

and subcellular membranes. $n lung tissuesand subcellular membranes. $n lung tissuesacting as a suractant in a comple! o a proteinacting as a suractant in a comple! o a proteinand lecithin. $n the eye, rhodopsin o rods is aand lecithin. $n the eye, rhodopsin o rods is alipoprotein comple!.lipoprotein comple!.

"ransport lipoproteins"ransport lipoproteins::

"hese are the orms present in blood plasma."hese are the orms present in blood plasma."hey are composed o a protein called"hey are composed o a protein calledapolipoproteinapolipoprotein and diMerent types o lipids.and diMerent types o lipids.(-holesterol, cholesterol esters, phospholipids(-holesterol, cholesterol esters, phospholipidsand triglycerides. *s the lipid contentand triglycerides. *s the lipid contentincreases, the density o plasma lipoproteinsincreases, the density o plasma lipoproteinsdecreasesdecreases

2lasma lipoproteins can be separated by2lasma lipoproteins can be separated byt th dt th d


84/94

two methodstwo methods:

/./. Altra&centriugationAltra&centriugation: Asing the rate o: Asing the rate oNoatation in sodium chloride solutionNoatation in sodium chloride solution

leading to their se


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y y y gy gdiameter and the least density. "hey containdiameter and the least density. "hey contain /&/&6K protein6K proteinonly andonly and +&K at+&K at. "he main lipid. "he main lipidraction is triglycerides absorbed rom theraction is triglycerides absorbed rom the

intestine and they containintestine and they contain small amountssmall amountsoothe absorbed cholesterol and phospholipids.the absorbed cholesterol and phospholipids.

b ery low&density lipoproteins (LDL orb ery low&density lipoproteins (LDL orpre&pre&

&lipoproteins&lipoproteins: "heir diameter is smaller"heir diameter is smallerthan chylomicrons. "hey contain aboutthan chylomicrons. "hey contain about %&/0K%&/0Kproteinproteinandand 0&K lipid0&K lipid. "he lipid content is. "he lipid content ismainly triglycerides ormed in the liver. "heymainly triglycerides ormed in the liver. "heycontain phospholipid and cholesterolcontain phospholipid and cholesterol more thanmore thanchylomicrons.chylomicrons.

c Low&density lipoproteins (LDL or Low&density lipoproteins (LDL or

&&lipoproteinslipoproteins: "hey contain"hey contain /0&60K proteins/0&60K proteinsininthe orm o apolipoprotein #. "heirthe orm o apolipoprotein #. "heir lipidlipidcontent varies rom +0&0K.content varies rom +0&0K."hey contain"hey containabout E0K o total blood cholesterol and 80Kabout E0K o total blood cholesterol and 80Ko total blood phospholipids. *s theiro total blood phospholipids. *s theirpercentage increases, the liability topercentage increases, the liability toatherosclerosis increases.atherosclerosis increases.

d ;i h d it li t i (;DLd ;i h d it li t i (;DL


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d ;igh&density lipoproteins (;DL ord ;igh&density lipoproteins (;DL or &&LipoproteinsLipoproteins: "hey contain"hey contain @&@@K@&@@Kproteinsproteinsin the orm o apolipoprotein *.in the orm o apolipoprotein *.

"hey contain"hey contain 8@&E@K lipids8@&E@K lipidsormed oormed ocholesterol (cholesterol (80K o80K ototal blood contenttotal blood contentand phospholipids (and phospholipids (E0KE0Ko total bloodo total bloodcontentcontent. "hey act as cholesterol. "hey act as cholesterol

scavengersscavengers, as their percentage, as their percentageincreases, the liability to atherosclerosisincreases, the liability to atherosclerosisdecreases. "hey are higher in emalesdecreases. "hey are higher in emalesthan in males. Due to their high proteinthan in males. Due to their high proteincontent they possess the highest density.content they possess the highest density.

e *lbumin&ree atty acids comple!:e *lbumin&ree atty acids comple!:$t is a$t is aproteolipid comple! withproteolipid comple! with K proteinK proteincontent associated with long&chain reecontent associated with long&chain reeatty acids or transporting them.atty acids or transporting them.

-holesterol:-holesterol:


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-holesterol: $mportance:$mportance:&& $t is the most important sterol in animal$t is the most important sterol in animal

tissues astissues as ree alcoholree alcoholor in an esterifedor in an esterifedorm (orm (with linoleicwith linoleic,, oleic, palmitic acids oroleic, palmitic acids orother atty acidsother atty acids..

'teroid hormones, bile salts and vitamin D'teroid hormones, bile salts and vitamin Dare derivatives rom it.are derivatives rom it.

"issues contain diMerent amounts o it that"issues contain diMerent amounts o it thatserve a structural and metabolic role, e.g.,serve a structural and metabolic role, e.g.,adrenal corte!adrenal corte!content is /0K,content is /0K,whereas,whereas,brain is 6K,brain is 6K,others 0.6&0.K.others 0.6&0.K.

'ource'ource::& $t is synthesized in the body rom$t is synthesized in the body romacetyl&-o* (/gmPday, cholesterol does notacetyl&-o* (/gmPday, cholesterol does note!ist in plants and is also taken in the diete!ist in plants and is also taken in the diet((0. gmPday as in, butter, milk, egg yolk,0. gmPday as in, butter, milk, egg yolk,brain, meat and animal at.brain, meat and animal at.

2hysical propeties:2h

ysical propeties:$t has a hydro!yl group


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y p pyon -, a double bond between -@ and -E, +asymmetriccarbon atoms and a side chain

o + carbon atoms. $t is ound in all animal cells, corpus luteum

and adrenal corte!, human brain(/%K othe solids.

$n the blood (the total cholesterol amountsabout 600 mgPdLo which 6P is esterifed,chieNy to unsaturated atty acids while theremainder occurs as the ree cholesterol.

CH3

CH3

HO

CH3

CH3

CH3

.holesterol

-hemical properties-hemical

properties$ntestinal bacteria$ntestinal bacteria


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p pp preduce cholesterol intoreduce cholesterol into coprosterol andcoprosterol anddihydrocholesteroldihydrocholesterol..

& $t is also o!idized into& $t is also o!idized into%&%&DehydrocholesterolDehydrocholesteroland urther unsaturatedand urther unsaturated

cholesterol with a second double bondcholesterol with a second double bondbetweenbetween -% and -+.-% and -+. 5hen the skin is5hen the skin is

irradiated with ultraviolet light %&irradiated with ultraviolet light %&

dehydrocholesterol is converted to vitamindehydrocholesterol is converted to vitaminD.D. "his e!plains the value o sun light in"his e!plains the value o sun light in

preventingpreventing ricketsrickets..

CH3

CH3

HO

CH3

CH3

CH3

.oprosterol,

in $eces

H

CH3

CH3

HO

CH3

CH3

CH3

5ihydrocholesterol,

in lood and other tiss%es

H

IrgosterolIr

gosterol diMers rom %&diMers rom %&


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IrgosterolIrgosteroldiMers rom %&diMers rom %&dehydrocholesterol in the side chain.dehydrocholesterol in the side chain.Irgosterol is converted to vitamin D6 byIrgosterol is converted to vitamin D6 by

irradiation with A Irgosterol and %&irradiation with A Irgosterol and %&dehydrocholesterol are called 2ro&vitaminsdehydrocholesterol are called 2ro&vitamins

D or precursors o vitamin D.D or precursors o vitamin D.

& $t was frst isolated rom ergot, a ungus& $t was frst isolated rom ergot, a ungus

then rom yeast. Irgosterol is less stablethen rom yeast. Irgosterol is less stablethan cholesterol (than cholesterol (because o having because o having double bondsdouble bonds..

CH3

CH3

HO

CH3

CH3

CH3

6"dehydrocholesterol

CH3

CH3

HO

CH3

CH3

CH3

0rgosterol

CH3

'teroids'teroids


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'teroids constitute an important class'teroids constitute an important classo biological compounds.o biological compounds.

'teroids are usually ound in'teroids are usually ound inassociation with at. "hey can beassociation with at. "hey can beseparated rom ats ater saponifcationseparated rom ats ater saponifcationsince they occur in the unsaponifablesince they occur in the unsaponifableresidue.residue.

"hey are"hey are derivatives o cholesterolderivatives o cholesterolthatthatis ormed o steroid ring or nucleus.is ormed o steroid ring or nucleus. #iologically important groups o substances,#iologically important groups o substances,

which contain this ring, are:which contain this ring, are:/./. 'terols.'terols.

6.6. *drenal cortical hormones.*drenal cortical hormones... >ale and emale se! hormones.>ale and emale se! hormones.8.8. itamin D group.itamin D group.@.@. #ile acids.#ile acids.E.E. -ardiac glycosides.-ardiac glycosides.

9eneral consideration about naturally occurring9eneral consideration about naturally occurringt idt id


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steroidssteroids:

* typical member o this group* typical member o this group is cholesterolis cholesterol..-ertain acts have to be considered when drawing-ertain acts have to be considered when drawing

steroid ormulasteroid ormula:/ "here is always o!ygen in the orm o/ "here is always o!ygen in the orm o hydro!yl orhydro!yl or

ketone on -ketone on -..

6 Bings6 Bings - and D are saturated- and D are saturated(stable.(stable.

>ethyl groups at >ethyl groups at -/+ -/-/+ -/. $n case o vitamin D,. $n case o vitamin D, thethe

-;-;group at -/ becomes a methylene groupgroup at -/ becomes a methylene group(G-;6 and the ring # is opened, whereas,(G-;6 and the ring # is opened, whereas, thisthismethyl group is absent in emale se! hormonesmethyl group is absent in emale se! hormones(estrogens.(estrogens.

8 $n estrogens (emale se! hormones ring * is8 $n estrogens (emale se! hormones ring * isaromatic and there isaromatic and there is no methyl group on -/0.no methyl group on -/0.

CH3

CH3

HO

Steroid ring

!2

3 4

6

78

!9

!!

!2

!3

!4 !

!!6

!7

!8

A :

. 5

#ile acids#ile acids:


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"hey are produced rom o!idation o cholesterol"hey are produced rom o!idation o cholesterolin the liver producingin the liver producing cholic andcholic andchenodeo!ycholic acidschenodeo!ycholic acidsthat are con7ugatedthat are con7ugated

withwith glycine or taurineglycine or taurineto produceto produce glycocholic,glycocholic,glycochenodeo!ycholic,glycochenodeo!ycholic, taurocholictaurocholicandandtaurochenodeo!ycholic acids. "hey react withtaurochenodeo!ycholic acids. "hey react withsodium or potassium to producesodium or potassium to produce sodiumsodiumororpotassium bile saltspotassium bile salts..

"heir unction is as ollows"heir unction is as ollows:

/./. Imulsifcation o lipids during digestion.Imulsifcation o lipids during digestion.6.6. ;elp in digestion o the other oodstuMs.;elp in digestion o the other oodstuMs.

.. *ctivation o pancreatic lipase.*ctivation o pancreatic lipase.

8.8. ;elp digestion and absorption o at&soluble;elp digestion and absorption o at&solublevitamins.vitamins.

@.@. 'olubilizing cholesterol in bile and prevent gall'olubilizing cholesterol in bile and prevent gallstone ormation.stone ormation.

E.E. -holeretic action (stimulate their own-holeretic action (stimulate their ownsecretion.secretion.

%.%. $ntestinal antiseptic that prevent putreaction$ntestinal antiseptic that prevent putreaction


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CH3

CH3

HO

CH3

C

Sodi%"ta%ro orglyco"cholate

CH3

CH3

HO

CH3

C

Sodi%"ta%ro orglyco"chenodeo#ycholate

OH

OH OH

O O

R1'r R2 R1'r R2

(CH2)2 &O3Na+H2N

CH2 COONa+H2N

Sodi% ta%rateSodi% glycate

;! ;2

9.10. Biokimia Lipid Bu Ina

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