CARBOHYDRATES FxnMain source of ENERGY + STORAGE + STRUCTUAL components DNA Ribose Plant cell wall Cellulose

StructureC:H:O = 1:2:1 (CH2O)nIsomers = same chemical formula, diff structureEpimer = configuration around one carbon differs

4 types of Carb1. Monosaccharides simplest carbs // building blocks

Glycerose/Glyceraldehyde (aldose,3)Erythrose (4)Ribose, Xylose (5)Glucose (aldose,6), Fructose (ketose), Galactose, MannoseClassified by: Number of carbons: Trioses, Pentose, Hexose Functional group: Aldose (RCOH), Ketose (RCOR) Isomerism: look at chiral C above CH2OHD-form (OH on R)L-form (OH on L) Note: AAs mostly L; Carbs mostlyD- Sugar Derivatives OH group replaced by -NH2

2. Disaccharides joined by Glycosidic bonds via Condensation Maltose glucose + glucose; via MaltaseSucrose glucose + fructose; via SucraseLactose glucose + galactose; via LactaseAll disaccharides are reducing sugar EXCEPT sucroseMono --> Disaccharides via condensation (water lost)Mono 10 monoHomopolysaccharides (starch, glycogen, dextrans, glucans) Heteropolysaccharides (glycosaminoglycans)

Insoluble (very large molecules)Can be linear or branchedMostly used as: Storage (starch, glycogen) or Structural (cellulose) components

STORAGEGlucose homopolymers; alpha-1,4 glycosidic linkages

STARCH Major carb storage in PLANTS Amylose = unbranched form of starch Amylopectin = branched

GLYCOGEN Major carb storage in ANIMALS found in liver & skeletal m. Highly branched (alpha-1,6)

To cleave -1,4 : Glycogen Phosphorylase To cleave -1,6: Glucantransferase & Amylo- -1,6-Glucosidase Glucose units of glycogen can now enter glycolytic pathwayBoth amylose & amylopectin are rapidly hydrolyzed by Amylase, which is secreted by the pancrease & parotid glands

INULINHomopolymer of fructoseHighly water solubleUsed to determine GFR (glomerular filtration rate)

STRUCTUAL (Proteoglycans)CELLULOSECHITIN

CELLULOSE Major structural carbohydrate in PLANTS Unbranched glucose homopolymers; beta-1,4 linkage Mammals cant digest this

GAGs (Glycos-amino-glycans) Most abundant heteropolysaccharide in the body 95% carbohydrate + uronic aicd (amono sugar derivative, either Nam, or Nam Contain mostly carbohydrate (95% or more) Most abundant heteropolysaccharide in the body Are long unbranched polysaccharides containing a repeating disaccharide unit of the disaccharide is always an amino sugar derivative, either NAM or NAG *** Bacterial cell walls contains a heteropolysaccharide made up of alternating NAG and NAM units The other is usually a uronic acid, such as glucuronic acid, giving a negative charge GAGs are highly negatively charged molecules, with extended conformation that imparts high viscosity to the solution Located primarily on the surface of cells or in the extracellular matrix Along with the high viscosity of GAGs comes low compressibility, which makes these molecules ideal for a lubricating fluid in the joints At the same time, their rigidity provides structural integrity to cells and provides passageways between cells, allowing for cell migration GAGs function as important structural components of CT (which includes adipose tissue, cartilage, and bone as well as collagenous, elastic, and reticular fibers) Most important physicochemical property of CT which is regulated by its mucopolysaccharide molecule is Viscosity The extracellular space In animal tissue is filled with a gel-like material, the extracellular matrix, also called ground substance, which holds the cells of a tissue together and provides a porous pathway for the diffusion of nutrients and oxygen to individual cells Chondroitin sulfate & hyaluronic acid are components of extracellular matrix Hyaluronidase is most likely to promote depolymerization of the ground substance or Extracellular Matrix (different Q) The ground substances is composed of an interlocking meshwork of heteropolysaccharides (glycosaminoglycans) most covalently linked to protein forming proteoglycans and fibrous proteins

GAGLocalizationComments

Hyaluronic acidSynovial fluid, vitrous humor of the eye, ECM of loose CTLarge polymers, serves as a lubricant and shock absorber (why its perfect for jts)

Chondroitin sulfateCartilage, tendons, ligaments and aortaMost abundant GAG of extracellular matrix - Cartilage is ABUNDANT!

Heparin sulfateBasement membranes, components of cell surfacesContains higher acetylated glucosamine than heparin

HeparinComponent of intracellular granules of mast cells that line the arteries of the lungs, liver and skinServes as an anticoagulant

Dermatan sulfateSkin, blood vessels, heart valves

Keratan sulfateCornea, bone, cartilage aggregated with chondroitin sulfates Primarily in CartillageMost heterogenous GAG

Which one is NOT a GAG??? They are all Sulfates, Except, Heparin and Hyaluronic Acid So know all of the above!!! Hyaluronic acid/Hyaluronate Is a repeating polymer of a disaccharide of glucuronic acid and N-acetylglucosamine Is a lubricating material in the synovial fluids of joints such as the elbow or knee Acts as the cement substance of tissue Synthesized in the golgi apparatus is a highly polar polyanion Is unique among the GAGs in that it contains no sulfur and does not covalently link to protein to form proteoglycans Is found in extracellular matrix, and is a very long filament structurally So it does not have compact folded structure Long and straight wieners can make her (or him) GAG!!! Another Q: Depolymerization of ground substance occurs via hyaluronidase (not collagenase) Hyaluronidase is an enzyme that hydrolyzes hyaluronic acid Chondroitin sulfate: Primarily found in cartilage, however, small amounts are found in bone Fxns as part of the ECM Is a polymer of a repeating unit comprising alpha (1-3) linked disaccharide of glucuronic acid and N-acetylgalactosamine Galactosamine is largely sulfated on the hydroxyl of carbon 6 Keratan sulfate (aka keratosulfate): Is found in the cornea of the eye and in cartilage Occurs primarily in cartilage Consists of alternating units of sulfated N-acetylglucosamine and D-glucuronic acid Heparin sulfate: Occurs in the cell membrane of most cells Is type IV collagen Basement Membrane It consists of alternating units of a sulfated N-acetylglucosamine and either L-glucuronic acid or L-iduronic acid, which also may be sulfated Dermatan sulfate: Found mostly in the skin It consist of alternating units of a sulfated N-acetylgalactosamine and L-iduronic acid, which is sometimes sulfated Proteoglycans: Consist of a Large Hyaluronate fiber (polymer of disaccharide) and attathed to it is core proteins with glycosaminoglycan (GAGs) attached in a brush like fashion The ground substance of the extracellular matrix is a highly hydrated gel containing large polyanionic proteoglycans molecules, which are about 95% polysaccharide and 5% protein The linkages of GAGs to the core protein involves a specific trisaccharide composed of two galactose residues and one xylose residue The carbohydrate chain is referred to as a glycosaminoglycans, which can bind covalently to a protein core The protein cores are rich in serine and threonine residues (-OH groups), which allows multiple GAG attachments The large # of alcohol groups on the polysaccharide chains contributes to the water-binding properties of proteoglycans via hydrogen bonding So OH for binding GAGs and for binding H20 Another Q: Each of the following applies to proteoglycans: Polyanion Hydrophilic Highly charged Sulfated sugars Linear structure

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Reducing Sugars

(CARD1)Can be oxidized to carboxylic acids bc it contains one free anomeric carbon(carbonyl group) we can thus use common oxidizing agents to test for the presence of a reducing sugar in tests for: Diabetes screening (excess glucose in blood) Glocusuria screening (excess glucose in urine)

Remember the reducing agent gets oxidized and the oxidizing agent gets reducedGlucose, Fructose, Galactose, Maltose, LactoseNOT SUCROSE (no anomeric carbon)!!Some carbohydrates convert Cu2+ ions to Cu+ ions; this property is related to their ability to act as a reducing agent (ionic state gets less positive, ex from 3+ to 2+ meaning its reduced). The opposite is true for an oxidation.

Glycosidic bond

(CARD1)Covalent bonds form when OH group on anomeric carbon of a monosaccharide reacts with -OH or -NH group of another compound (typically an alcohol, purine, pyrimidine, or in this case another sugar); Maltose, lactose and sucrose consists of monosaccharides joined by an O-glycosidic boneIf oxygen is involved, this bond is classified as O-glycosidic, if nitrogen is involved this bond is classified as N-glycosidic