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Carbohydrates

Carbohydrates. Dr. Nasim AP Biochem. Monosaccharides (Single sugar residue). 3 C: Trioses 4 C: Tetroses 5 C: Pentoses 6 C: Hexoses 6 C: Hexoses. Monosaccharides (Single sugar residue). (Aldose) ( ketose ) Glyceraldehydes DHA - 3 C

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Carbohydrates

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  1. Carbohydrates Dr. Nasim AP Biochem Dr. Nasim

  2. Monosaccharides (Single sugar residue) • 3 C: Trioses • 4 C: Tetroses • 5 C: Pentoses • 6 C: Hexoses • 6 C: Hexoses Dr. Nasim

  3. Monosaccharides (Single sugar residue) • (Aldose) (ketose) • Glyceraldehydes DHA - 3 C • Erythrose Erthrulose - 4 C • Ribose Ribulose - 5 C • Xylose Xylulose 5 C • Glucose Fructose - 6 C Dr. Nasim

  4. Monosaccharides • Aldoses: Those Monosaccharides which contain Aldehyde group. (H-C=O) • Ketose: Those Monosaccharides which contain keto group. (C=O) Dr. Nasim

  5. Monosaccharides • Anomeric carbon: Aldoses & Ketose may cyclize to produce an Anomeric carbon. • Anomeric carbon contain reactive hydroxyl group. Dr. Nasim

  6. Monosaccharides • If the Reactive hydroxyl group is free (Not attached to any other molecule) then the sugar is known as reducing sugars. • Reactive hydroxyl group may attached covalently to another molecule. • N-Glycosidic linkage: If the Reactive hydroxyl group is attached to–NH2 group. Dr. Nasim

  7. Monosaccharides • O-Glycosidic linkage: If the Reactive hydroxyl group is attached to–OH group. • ISOMERS: If 2 compound have the same chemical formula. E.g. Fructose & glucose are isomers of each other. Dr. Nasim

  8. Monosaccharides • Epimers: If 2 compound have the same chemical formula but the differ in configuration around 1 specific C atom. • Galactose & glucose are C 4 Epimers of each other. • Mannose & glucose are C 2 Epimers of each other. Dr. Nasim

  9. Monosaccharides • Enantiomers: If 2 compound are mirror image of each others. • E.g. L - Glucose & D – Glucose. • The configuration of asymmetric carbon atom farthest from the aldehyde or keto group (with reference to D or L glyceraldehydes) determines whether a monosaccharide is of D or L series. • In D form OH gp is on right side & vice versa in left side. Dr. Nasim

  10. Disaccharides(2 Monosaccharides units) • Sucrose = Glucose + Fructose • (α1-2 linkage) • Lactose = Glucose + Galactose • (β1-4 linkage) • Maltose = Glucose + Glucose • (α1-4 linkage) • Iso-malotose = Glucose + Glucose (α1-6) Dr. Nasim

  11. Oligosaccharides(3-10 Monosaccharides) • E.g. Maltotriose: Compose of 3 Glucose residues. Dr. Nasim

  12. Polysaccharides(>10 Monosaccharides units) • Homo Polysaccharides (contain same type of monosaccharides) • Glycogen which is also known as animal starch. • Dextrin • Dextran • Cellulose Dr. Nasim

  13. Polysaccharides • Hetero Polysaccharides • (contain same type of monosaccharides or different monosaccharides along with prosthetic groups) • Muco Polysaccharides • Mucilages • Hemicellulose Dr. Nasim

  14. Polysaccharides • Hetero Polysaccharides • Muco Polysaccharides • Hyaluronic acid • Heparin • Chondroitin sulphate • Blood group Polysaccharides. • Serum mucoids Dr. Nasim

  15. Polysaccharides • Hetero Polysaccharides • Mucilages • Agar • Vegetable • Pectin Dr. Nasim

  16. Monosaccharides • Glyceraldehydes: • Reference sugar • All sugars are derived from it • D & L forms are refer to it • DHA • Produced from glucose in glycolysis & also from glycerol which is produced in break down of fats Dr. Nasim

  17. Monosaccharides • Erythrose & Erthrulose • Produced from glucose in HMP shunt • Can be converted to glucose • Ribose • Produced from glucose in HMP shunt • Ribose component of RNA • Deoxy-Ribose component of RNA Dr. Nasim

  18. Monosaccharides • Ribulose, Xylose & Xylulose • Produced from glucose in HMP shunt Dr. Nasim

  19. Monosaccharides • Glucose • Grape sugar • Dextrose • Dextro-rotation • Most common source sucrose which is table sugar • Main source of energy for body & specially brain. Dr. Nasim

  20. Monosaccharides • Glucose (Cont.) • FBS 60 – 100 mg/dl • RBS 100 – 160 mg/dl • On reduction glucose forms alcohol e.g. Sorbitol • On oxidation sugar acids • Gluconic acid If oxidation of C1 of glucose Dr. Nasim

  21. Monosaccharides • Glucose (Cont.) • Glucuronic acid If oxidation of C6 of glucose • Glucaric acid If oxidation of C1& C6 of glucose • Glucuronic acid is used for detoxification of various toxic substances Dr. Nasim

  22. Monosaccharides • Galactose • Main source Lactose which is milk sugar • C 4 epimer of glucose • Mannose • Can be converted to glucose • On reduction forms Mannitol Dr. Nasim

  23. Monosaccharides • Fructose • Levulose. • Levo-rotation. • Sweetest among all sugars. • Most common source Sucrose (table sugar). • Pure honey = Fructose only. • Fructose  Glucose. • Entry into cells is independent of Insulin. • Source of energy for sperms. Dr. Nasim

  24. Disaccharides • Maltose = Glucose + Glucose (α1-4) • Fruit sugar • Reducing sugar • Produced from starch by hydrolysis due to salivary & pancreatic amylase. • Hydrolyzed by Maltase Dr. Nasim

  25. Disaccharides • Lactose = Glucose+ Galactose (β1-4) • Milk sugar • Reducing sugar • Hydrolyzed by Lactase Dr. Nasim

  26. Disaccharides • Sucrose = Glucose + Fructose (α1-2) • Cane sugar • Table sugar • Non-reducing sugar • Invert sugar • Hydrolyzed by Sucrase (Invertase) Dr. Nasim

  27. Polysaccharides • Homo Polysaccharides • Glycogen • Store from of Glucose • Present mostly in Liver & Muscles. • Animal starch • Branched structure (Tree like) • Less then 12 glucose residues Dr. Nasim

  28. Polysaccharides • Homo Polysaccharides • Glycogen (Cont.1) • Within a chain (α1-4) broken by Phosphorylase enzyme. • At branch point (α1-6) broken by de-branching enzyme. • Blood glucose levels are usually maintained by Liver glycogen stores. Dr. Nasim

  29. Polysaccharides • Homo Polysaccharides • Starch • Most of dietary carbohydrates are in this form. • 2 types • Amylose (Straight chain) • Amylopectin (Branched structure) more then 12 residues in each chain. Dr. Nasim

  30. Polysaccharides • Homo Polysaccharides • Starch (Cont.) • Hydrolyzed by salivary & Pancreatic amylase into Maltose, Maltotriose & dextrins. Dr. Nasim

  31. Polysaccharides • Homo Polysaccharides • Dextrins • Intermediate product of hydrolysis of starch. • E.g. Amylodextrins, Erythrodextrins & Achrodextrins. Dr. Nasim

  32. Polysaccharides • Homo Polysaccharides • Dextrans • Highly viscous. • Plasma expander. • Cellulose • Can’t be digested. • Increase bulk of stool. Polysaccharides Dr. Nasim

  33. Polysaccharides • Hetero Polysaccharides • Muco Polysaccharides • Animal origin • Mucoprotein & Mucin (when in combination with proteins) Dr. Nasim

  34. Polysaccharides • Hetero Polysaccharides • Muco Polysaccharides • Subtypes • Hyaluronic Acid • Chondroitin sulphate • Heparin • Blood group Polysaccharides • Serum mucoids Dr. Nasim

  35. PolysaccharidesMuco Polysaccharides • Hyaluronic Acid (Cementing agent) • Present in skin, synovial fluid, seminal fluid & vitreous humor. • Functions • Prevents penetration of bacteria into skin • Lubrication of the joints • Helps in fertilization • Hydrolyzed by Hyaluronidase Dr. Nasim

  36. PolysaccharidesMuco Polysaccharides • Chondroitin sulphate Dr. Nasim

  37. PolysaccharidesMuco Polysaccharides • Heparin Dr. Nasim

  38. PolysaccharidesMuco Polysaccharides • Blood group Polysaccharides Dr. Nasim

  39. PolysaccharidesMuco Polysaccharides • Serum mucoids Dr. Nasim

  40. Polysaccharides • Mucilages • Plant origin • Agar • Non-digestible • Laxative • Culture media Dr. Nasim

  41. Polysaccharides • Vegetable gums • Used in pharmaceutical industry • Pectins • For making jellies • Hemicellulose Dr. Nasim

  42. Asymmetric carbon atom • Asymmetric carbon atom: The carbon atom to which 4 different chemical groups are attached & it can rotate plain polarized light to the right or to the left. • E.g. Open chain formula of Glucose contains 4 Asymmetric carbon atoms. (C2, 3, 4 & 5). • E.g. Close chain formula of Glucose contains 5 Asymmetric carbon atoms. (C1, 2, 3, 4 & 5). Dr. Nasim

  43. Optical Isomers • Those sugars which rotates plain polarized light to right are (d) sugars & which to left are (l) sugars. • Racemic Mixture: • Such a solution which contains equal amount of Levo & dextro-rotatory then rotation of light will be equal but in opposite direction. Dr. Nasim

  44. Ring Structure • Hemiacetal ring: if the ring is formed by aldehyde gp. • Hemiketal ring: if the ring is formed by keto gp. • Pyranose Ring: 6 sided ring. O2 bridge b/w C1 & C5. • Furanose Ring: 5 sided ring. O2 bridge b/w C1 & C4. Dr. Nasim

  45. Anomeric carbon • C of Aldehyde or keto gp forming hemiacetal or Hemiketal rings. • C1 in Aldo-sugars. E.g. glucose • C2 in keto sugars. E.g. fructose Dr. Nasim

  46. Mutarotation • The direction of plain polarized light in a freshly prepared glucose solution goes on changing for some time before settling to specific direction. • Reason: unfolding of ring structure to striaght chain in order to maintain equilibrium b/w α & β forms of sugars. Dr. Nasim

  47. Phenomenon of Inversion Dr. Nasim

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