Chemical properties of monosaccharides

1. Chemical properties of
monosaccharides
Reaction with hydrazines to form osazones.
Reduction to form sugar alcohols
Name of monosaccharide Sugar derivative
Glucose Sorbitol
Mannose Mannitol
Galactose Dulcitol
Fructose Sorbitol and
Mannitol
Ribose Ribitol
Glyceraldehyde Glycerol
Dihydroxyacetone Glycerol

2. Mannitol acts as diuretic and used in the
patients of cerebral edema.
Sorbitol gets deposited in the lens of the
diabetic patient and contributes to an early
cataract formation.

3. Oxidation to produce sugar acids
Gluconic acid,Glucuronic acid,Glucaric acid
Gluconic acid is of great physiological
importance,used in the detoxification and
inactivating many substances like benzoic
acid,steroid hormones,bilirubin etc.

4. Reducing action of sugars in alkaline solutions
Action of acids and bases
Formation of esters
1.Phosphates
acetates,propionates,stearatesetc.
2.Glucose catabolism
3.Nucleoproteins

5. Several sugar esters important
in metabolism

6. Formation of amino sugars
1.Hexosamines(D-glucosamine,D-galactosamine
and D manosamine).
2.Constituent of Glycosaminoglycans.
Fermentation

7. Special monosaccharides: amino sugars
Constituents of mucopolysaccharides

8. FORMATION OF GLYCOSIDES.
Compounds in which carbohydrate residue is
attatched by an acetal linkage at the anomeric
carbon atom to an alcoholic residue called
aglycone which is a non carbohydrate.

10. The aglycone may attach through to sugar
through –OH or -NH2 group forming O
and
N-glycosides.
Aglycone may be methyl alcohol,a
sterol,phenol,a purine or a
pyrimidine(sugar nucleosides),a
protein(glycoproteins,GAG’s) and
lipids(glycolipids).

11. Physiologically important glycosides.
Cardiac glycosides
Streptomycin
Ouabain
Glucovanillin

13. Deoxy sugars.
Oxygen of the hydroxyl group is removed.
Most important deoxy sugar is 2’-deoxy-D-
ribose.

14. Component of DNA
L- fucose(deoxy L-galactose) in milk and blood
group substances.
2-deoxy glucose is used in research.

15. Some important Monosaccharides.
HEXOSES
D-GLUCOSE.
Grape sugar or dextrose.
Form glycogen, starch and cellulose.
Represents almost 100% of monosaccharides in blood
therefore known as blood sugar.
Found in the urine of diabetics
Sorbitol.sugar acids
Can occur in pyran and furan form
74% as sweet as sucrose.

16. FRUCTOSE
Fruit sugar and levulose.
Occurs in honey and plant kingdom.
Source of energy for spermatozoa.
Occur in pyran and furan form
Constituent of sucrose.
Sweetest of all sugars(173%) of sucrose

17. GALACTOSE.
Part of lactose,seed coat of legumes.
Constituent of glycolipids and glycoproteins.
32% sweeter than sucrose.
MANNOSE
Constituent of glycoproteins
In the body turns into glucose

18. PENTOSES
Monosaccharides contain ring of five atoms.
Constituent of nucleic
acids,ATP,GTP,CTP,UTP,NAD+,NADP+,FMN,FAD
and coenzyme A.
Phosphates as intermediates in the pentose
phosphate pathway of glucose metabolism.
L-Xylulose is intermediate in uronic acid pathway
of glucose metabolism.

19. D-lyxose is found in heart muscle.
D-arabinose and D-Xylose is found in
glycoproteins.