Carbohydrate Chemistry

An Edited Version of an Already Existing Carbohydrate Presentation from SlideShare

1. Carbohydrate Chemistry Structure and Isomerism

2. Structure of Monosaccharides

3. Straight chain Ring structure Chair form

4. Isomerism The compounds possessing identical molecular formula but different structures are called isomers. Various types of isomerism Structural isomerism Stereoisomerism

5. Structural I somerism Same molecular formulae but differ from each other by having different structures.

6. Stereoisomerism Same molecular formula and same structure but they differ in configuration. That is, they differ in the arrangement of their atoms in space. Presence of asymmetric carbon atoms allow the formation of stereoisomerism

7. Stereoisomerism The important types of stereoisomerism associated with glucose are

8. D and L Enantiomerism “ Handedness” Stereoisomers that are nonsuperimposable mirror images of each other. Handedness (D and L forms) is determined by the configuration at the high-numbered chiral carbon.

9. D and L Enantiomerism “ Handedness”

10. Optical I somerism Optical activity is the capacity of a substance to rotate the plane polarized light passing through it.

11. Optical Isomerism Chiral compounds rotate polarized light clockwise or counter clockwise through a certain angle

12. Epimerism Epimerism is the stereoisomerism if two monosaccharides differ from each other in their configuration around a single specific carbon ( other than anomeric) atom.

13. Epimerism

14. Anomerism These are isomers obtained from the change of position of hydroxyl group attached to the anomeric carbon e.g.  and  glucose are 2 anomers . Also  and  fructose are 2 anomers .

15. Anomerism

16. Mutarotation is defined as the change in the specific optical rotation by the interconversion of α and β forms of D glucose to an equilibrium mixture Mutarotation

17. Structure of Oligosaccharides Disaccharides

18. Disaccharides These are glycosides formed by the condensation of 2 simple sugars. If the glycosidic linkage involves the carbonyl groups of both sugars ( as in sucrose ) the resulting disaccharide is non-reducing. On the other hand, if the glycosidic linkage involves the carbonyl group of only one of the 2 sugars (as in maltose and lactose) the resulting disaccharide is reducing.

19. Polysaccharides These are formed by the condensation of n molecules of monosaccharides with the removal of n -1 molecules of water. Since condensation involves the carbonyl groups of the sugars, leaving only one free carbonyl group at the end of a big molecule, polysaccharides are non-reducing . They are of 2 types: Homopolysaccharides (e.g. starch, glycogen, cellulose). Heteropolysaccharides (e.g. glycosaminoglycans , glycoproteins)

20. - 1,4 linkage between two glucose units -1,6 linkage between two glucose units

21. The ability to digest cellulose is found only in microorganisms that contain the enzyme Cellulase . Certain animal species (e.g. Cow) utilize such organisms in their digestive tracts to digest cellulose

22. Aldehyde group H-C=O Monosaccharides Enantiomers if they are Nonsuperimposable m irror images of each other can link to form Disaccharides e.g., S ucrose = glucose + fructose Lactose = galactose + glucose Maltose = glucose + glucose Oligosaccharides Polysaccharides can be Homo- e.g., Starch, glycogen, cellulose Hetero- e.g., GAGs Epimers Differ in configuration around one specific carbon atom Isomers if they have Same chemical formula Ketoses Ketone group C=O Can be classified as if they if they contain if they contain Aldoses Tri - Tetra- Penta -