LSM1101_Lipids_2C
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Transcript of LSM1101_Lipids_2C
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Lipid-2b Classification
Metabolism
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Classification
Fatty acids
Triacylglycerols
Phosphoglycerides
Sphingolipids Steroids
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As major components of lipid molecules (triglycerides,phospholipids, sphinomyelin)
Precursors to other molecules (prostaglandins)
Provide energy (through oxidation processes)
Industrial uses (soaps, etc)
1. Fatty acid
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1. Fatty acid
Mostly have 14-20 carbons
Even number of carbons
Two numbers m:nm = number of carbonsn = number of C=C bonds
Double bonds are mostly cis
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1 CH2 OH|
2 CH OH|
3 CH2 OH
Glycerol
2. Triglycerides
Fat storage in adipocytescauses type-2 diabetes andresistin aggravates it.
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3. Phosphoglycerides
(Glycerophospholipid or Phospholipid)
1 CH2 OH|
2 CH OH
|3 CH2 OH
Glycerol
Phospholipases
Degrade phospholipidsPresent in snake venomsCause inflammation,
fever, headache
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4. Sphingolipids
-Derivatives of Sphingosine and
Dihydrosphingosine-major components of membrane
-Functions:
-Cell-cell recognition
-Tissue immunity
-Impulse transmission
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5. Steroids
Steroids stem from a single template
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Lipid-Linked protein
Lipids and proteins covalently interact to form lipid-linked proteinsPrenylated; Fatty acetylated; Glycoinositol phospholipids
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Lipoproteins
Proteins and lipids non-covalently interact to form lipoproteins
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What is this?
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Lipid metabolism
* 1. Fatty acid degradation
-oxidationKetone body
2. Fatty acid biosynthesis
3. Triacylglycerol biosynthesis
* 4. Phospholipid degradation
5. Cholesterol biosynthesis
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1. Fatty acid degradation: -oxidation
Most fatty acids are degraded to form acetyl-CoAwithin mitochondria in a process called -oxidation
Production of ATP to provide energy (resulted
from oxidation of acetyl-CoA via citric acid cycle )Process found in all living organisms
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A Key molecule in lipid metabolism
Acyl-CoA: fatty acid + Co-A
Acetyl-CoA: acetyl form of Co-A
Acyl-CoA
Acetyl-CoA
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Acyl-CoA reacts with carnitine to form acylcarnitine which can then be transportedacross the inner membrane of mitochondria and is subsequently recovered asacyl-CoA
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The -oxidation of acyl-CoA molecules include four reactions that occur in themitochondria. Each cycle of reactions forms acetyl-CoA and acyl-CoA thats shorter bytwo carbons
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Most acetyl-CoA produced from fatty acid degradation is used in citric acid cycle togenerated energy
Excess acetyl-CoA is converted to ketone bodies (acetoacetate, b-hydroxybutyrateand acetone) in a process called ketogenesis.
Occurs in liver mitochondria
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2. Fatty acid biosynthesis
A mean by which energy is stored
Occurs within cytoplasm of most animal cells.However, liver is the major site for this process
Overall reaction (palmitic acid):
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Desaturation of fatty acids
Saturated fatty acids can bedesaturated
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Glycerol
Glucose
3. Triacylglycerol biosynthesis
Even if you do not take a lotof fatty food, triglycerides canbe synthesized from glucose
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4. Phospholipid degradation
Phospholipase A 2
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Phospholipid digestion byPhospholipase A 2 (PLA2)
Phospholipase A 2 cutsa phospholipid andreleases a fatty acid
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Phospholipase A 2 (PLA2) properties1 11 21 31 41 51 61
MiPLA1 NL LQFR K MIK CTVPG R EPLV AFT DYGCYCG KGGSGTPVDE LDRCCQTHD N CYDKA EKL PE CKGILS R PYV MiPLA2 NL YQFR K MIK CTIPG R EPLL AFT DYGCYCG KGGSGTPVDE LDRCCQTHD N CYDKA EKL PE CKGILS GPYV MiPLA3 NL LQFR K MIK CTIPG I EPLL AFS N YGCYCG KGGSGTPVDE LDRCCQTHD Y CYDKA KIH PE CKGILS GPSF MiPLA4 NL LQFR N MIK CTIPG R EPLL AFS N YGCYCG KGGSGTPVDE LDRCCQTHD N CYDKA EKL PE CKGILS GPYV
71 81 91 101 111 121 MiPLA1 NTYAYDCT KG KITCNDQ KDK CKLFICNCDR TAAMCFAKA R YI E AN NH IDP KR CK MiPLA2 NTYSYDCT DG KLTCNDQ KDK CKLFICNCDR TAAMCFAKA P YI E AN NH IDP NR CK MiPLA3 NTYAYDCT DG KLTCNDQ KDK CKLFICNCDR TAAMCFAKA P YKEEN NR IDA SN CK MiPLA4 NTYSYDCT DG KLTCNDQ N DK CKLFICNCDR TAAMCFAKA P Y N E AY NH FNR QL CK
Prothrombin time assay
Hydrolytic activity
0100200300400500600
700800900
MiPLA1 2 3 40
0.050.1
0.15
0.20.25
0.30.350.4
MiPLA1 2 3 4
Dark urine induction
0
20
40
60
80
100
120
140160
Control MiPLA1 2 3 4
Muscle necrosis assay
0200400600800
100012001400160018002000
Control MiPLA1 2 3 4
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5. Cholesterol biosynthesis
From acetyl-CoA, steroids aresynthesized
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