Disaccharides Invert sugar and other

role of disaccharides in the body and their significance in different disorders

1. DISACCHARIDES

2. DISACCHARIDES Sugars composed of two mono saccharide units joined by α -Glycosidic bond. MALTOSE14 SUCROSE 12 LACTOSE 14 LACTULOSE14 TREHALOSE11

3. MALTOSE

4. COMPOSITION O α- D- Glucopyranosyl (1-4) α -D- Glucopyranosyl MALT sugar SOURCES Malt, germinating cereals, enzymatic hydrolysis of starch by salivary & pancreatic Amylases. Maltase enzyme hdrolyzes Maltose into Glucose. strong reducing agent. Shows muta rotation. Forms sun flower shaped Osazone crystals.

5. ISOMALTOSE Enzymatic hydrolysis of branch points of the AMYLOPECTIN unit of Starch. Shows α -(1-6) linkage.

6. LACTOSE SOURCES Milk ,pharmaceutical preparations. COMPOSITION O- β -D- Galactopyranosyl (1-4)- β - D- Glucopyranosyl Synthesized in mammary glands ,can appear in the urine of lactating mothers.---LACTOSURIA. COW S’ milk contains 45% Lactose. Human milk contains 74% Lactose. Reducing sugar ,shows muta rotation.

7. LACTOSE INTOLERANCE Lactase deficiency Diarrhea ,flatulence , dehydration . Treatment Stop breast feeding/ milk intake. Yoghurt ,cheese & green vegetables for Ca ++ intake. Lactase pills.

8. LACTULOSE O- α –D Galactopyranosyl (1-4 )- β -D Fructopyranosyl SOURCES Heated Milk , synthetically produced . Can not be hydrolyzed by intestinal enzymes . Fermentation by intestinal bacteria . USES Mild Diuretic /osmotic laxative .

9. SUCROSE (TABLE SUGAR ) O α -D –Glucopyranosyl (1-2) β - D- fructofuranose sources Cane ,beetroot,sorgham,fruits & vegetables. Non reducing sugar , Does not form Osazone crystals. Does not exhibit muta rotation . Dextro rotatory sugar ( + 66.5 ) On hydrolysis it becomes strongly Levorotatory (- 28.2)

10. INVERT SUGAR Hydrolytic products of Sucrose are called invert sugars. Sucrose hydrolysis by Sucrase/ dilute acids liberates one molecule each of α D- Glucopyranose & β –D Fructofuranose. β D- Fructofuranose form is unstable & immediately gets converted to β –D Fructopyranose form, which is strongly Levorotatory ( -92 ) Overall effect is INVERSION of dextro rotatory Sucrose (+66.5) to Levorotatory.( - 22.8) Invert sugars are 33% more sweet than Sucrose i.e. Honey

11. TREHALOSE O α -D Glucopyranosyl (1-1) α -D Glucopyranosyl SOURCES Fungi, yeast

12. OLIGO SACCHARIDES 3-10 carbohydrate units. Components of integral membrane proteins, present on their extra cellular domain. Mostly contain Mannose /Sialic acid residues. Help in degradation of these integral proteins. EXAMPLES Glycoproteins Antibodies Coagulation factors