LEC(1): Carbohydrate Chemistry PDF

LEC(1):
 Carbohydrate Chemistry (1) => Quick Summary W.I.P By: Khaled Yahya HNU HBF  LEC(1): Carbohydrate Chemistry Dr.Mohammed I.Kotb Dr.Ahmed M.A. -Khaled Yahya =>Carbohydrates? -> [C(H 2 O)]n...

LEC(1):
 Carbohydrate Chemistry (1) => Quick Summary W.I.P By: Khaled Yahya HNU HBF  LEC(1): Carbohydrate Chemistry Dr.Mohammed I.Kotb Dr.Ahmed M.A. -Khaled Yahya =>Carbohydrates? -> [C(H 2 O)]n O What are carbohydrates? C The carbohydrates are a group of naturally occurring carbonyl compounds like Aldehydes or ketones that also contain several hydroxyl groups (Alcohols). O O (R-OH) C C R H R R Functions of carbohydrates? ->Primary energy source (e.g., glucose). ->Structural roles (e.g., cellulose in plants). ->Serve as precursors for other biomolecules (e.g., nucleotides). ->Play roles in cell signaling and recognition (glycoproteins, glycolipids).
 ->Part of drugs
 ->Disturbance in carbohydrate metabolism leads to metabolic diseases
 Ex. DM, Galactosemia, Lactose Intolerance Carbohydrates Disaccharides Oligosaccharides Monosaccharide Polysaccharides Monosaccharide Simplest carbohydrates that can not be hydrolysed into
 simpler units Produces 2 molecules of monosaccharide on hydrolysis Disaccharide Produces 3-10 molecules of monosaccharide on hydrolysis Olgiosaccharides Produces more than 10 molecules of monosaccharide on 
 Polysaccharides hydrolysis HNU HBF  LEC(1): Carbohydrate Chemistry Dr.Mohammed I.Kotb Dr.Ahmed M.A. -Khaled Yahya No. Name Example =>Monosaccharides 3 Trioses Glyceraldehyde -> Cannot be hydrolyzed further
 further -> C n H 2n O
n 4 Tetroses Erythrose -> Classified depending upon 5 Pentoses Ribose the number of carbon atoms -->
 6 Hexoses Glucose 7 Heptoses Sedoheptulose 9 Nonoses Neuraminic acid -> Or whether aldehyde or ketone groups are present No. Aldoses Ketoses 3 Glyceraldehyde Dihydroxyacetone 4 Erythrose Erythrulose 5 Ribose, Xylose Ribulose, Xylulose 6 Glucose, Galactose Fructose =>D-Glucose -> Most important natural monosaccharide
 -> Aliphatic aldehyde with six C atoms, five C that Pyranose carry a hydroxyl group. Furanose -> Glucose may come in 5 carbons or 4 carbons during cyclization called furanose and pyranose ->
 -> There are anomers when cyclization occurs.
 --- If the OH is in the left (up), it is beta --- If the OH is in the right (down), it is alpha HNU HBF  LEC(1): Carbohydrate Chemistry Dr.Mohammed I.Kotb Dr.Ahmed M.A. =>Structure and Projections Cyclization (ring form) Fischer Projection Haworth Projection HNU HBF  LEC(1): Carbohydrate Chemistry Dr.Mohammed I.Kotb Dr.Ahmed M.A. =>Structure and Projections HNU HBF  LEC(1): Carbohydrate Chemistry Dr.Mohammed I.Kotb Dr.Ahmed M.A. =>Biological Importance. TYPE EXAMPLES IMPORTANCE Glyceraldehyde ->Intermediates of glycolysis
 Trioses Dihydroxyacetone ->Precursor of glycerol (lipid synthesis)
 Tetroses D-Erythrose ->Intermediates of carbohydrate metabolisim ->Ribose & deoxy-ribose enter in the structure Ribose, of nucleic acids (RNA & DNA)
 Deoxy- ->Ribose enters in the structure of ATP, GTP
 Pentoses ribose,
 & other high energy phosphate compounds
 Arabinose,
 ->Ribose enters the structure of coenzymes
 NAD, NADP, and flavoproteins
 Xylose -> Arabinose and xylose are constituents of glycoprotein in plant and animal cell

 ->Final form of carbohydrate digestion (blood sugar)
 ->Glucose is converted to all carbohydrate forms in the body (glycogen, galactose, ribose)
 ->Glucose is the major source of energy in Glucose mammals (dextrose)
 ->Excess in the blood is called hyperglycemia, presence in urine (glucosuria) is diabetes mellites
 Cataract due to sorbitol (reduced form of Hexoses glucose) ->It is the another (15%) source of energy in mammals.
 ->Main nutritional source of energy for the Fructose spermatozoa and is found in the seminal fluid.
 -> Can be converted to glucose in the liver and is the sweetest sugar Can be converted into glucose in liver, Galactose synthesized in mammary glands to make milk sugar (lactose) Mannose Mannose as constituents of many glycoproteins HNU HBF  LEC(1): Carbohydrate Chemistry Dr.Mohammed I.Kotb Dr.Ahmed M.A. =>Isomerism -->Structural Isomerism ->Same Molecular formula but different structures
 ->They differ in the functional group. Aldehyde Ketone HNU HBF  LEC(1): Carbohydrate Chemistry Dr.Mohammed I.Kotb Dr.Ahmed M.A. -->Stereoisomerism (Optical Isomers) ->Same Molecular formula but they differ in orientation of OH and H around one or more asymmetric carbon atom
 How to know D or L?
 Look at the 2nd last C direction Left or Right
 D = Right L = Left Asymmetric carbon (Chiral Center) HNU HBF  LEC(1): Carbohydrate Chemistry Dr.Mohammed I.Kotb Dr.Ahmed M.A. --> Optical Activity -> The ability of sugar to rotate plane polarized light to an angle, (light moving in one direction) measured by polarimeter
 (sugar) (sugar) Racemase Racemase can convert dextrorotatory into *NOTE Levorotatory using a racemic mixture ->There is a difference between D-Glucose and d-glucose (same goes for L and small l) ->As mentioned before, L and D depends on the direction of the OH in 2nd last C atom.
 ->For d and l small, it depends on the optical activity and not the direction of OH. (clockwise or counter-clockwise HNU HBF  LEC(1): Carbohydrate Chemistry Dr.Mohammed I.Kotb Dr.Ahmed M.A. -->Epimers
 -> A type of optical isomer
 -> Has more than one asymmetric carbon atom however -> All asymmetric carbon atoms are same except one. HBF  LEC(1): Carbohydrate Chemistry Dr.Mohammed I.Kotb Dr.Ahmed M.A. -->Anomers
 -> The alpha and beta form of any sugar in a cyclic (ring) structure. HBF  LEC(1): Carbohydrate Chemistry Dr.Mohammed I.Kotb Dr.Ahmed M.A. -->Enantiomers
 -> the D and L of any sugar. -> Mirror images of each other.
 -> Flip the asymmetric carbons -->Enzymes & Isomerism

 -> Enzymes distinguish between two isomers and use one or the other preferentially.
 -> Ex. Glycogen is synthesized from a-D-glucopyranose.
 -> Ex. Cellulose is synthesized from b-D-glucopyranose. -->Mutarotation

 -> Cyclic a and b anomers of sugar in solution are in equilibrium, so they can interconverted spontaneously, this process is called Mutarotation. HBF  LEC(1): Carbohydrate Chemistry Dr.Mohammed I.Kotb Dr.Ahmed M.A. -->Monosaccharide derivatives 1.Sugar Phosphate -> In metabolism, sugars need to be attached to a phosphate, they become phosphate esters.
 -> Examples: Ribose 5-phosphate, Glucose 6-Phosphate. 2.Deoxy-Sugar -> One oxygen got removed, so it’s called Deoxy -> The hydroxyl group is replaced by a hydrogen atom. -> Memorize one example: 2-Deoxy-D-Ribose. 3.Amino sugars -> Replaces OH at C2 by Amino group (NH )
 -> The hydroxyl group is replaced by Amino group. 2 -> Sometimes, the amino group is acetylated. -> Examples: Glucosamine, N-Acetyl-Galactosamine. 4.Sugar Alcohols -> Occurs after reduction.
 -> Reducing the carbonyl oxygen of the parent monosaccharide produces polyhydroxy alcohol.
 -> Examples: Glycerol (lipids) and Ribitol (FMN & FAD) Sugar Acids -> Carboxylic acids derived from aldoses.
 -> It occurs by the oxidation of the carbon, and which carbon
 specifically.
 -> If C-1 ---> Aldonic acid, Last carbon ---> Alduronic Acid
 HBF