CARBOHYDRATES Karaganda 2014y. KARAGANDA STATE MEDICAL UNIVERSITY

Brief contents. 1. Carbohydrates. Classification. A biological role. 2. Monosaharidy-pentose, aldose, ketose. 4. Chemical properties monosaccharides. 5. Аминосахара their properties, the basic representatives. 6. Separate representatives monosaccharides: glucose, fructose, a biological role.

CARBOHYDRATES Formerly the name "carbohydrate" was used in chemistry for any compound with the formula C m (H 2 O)n Monosaccharide Disaccharides Oligosaccharides and polysaccharides

MONOSACCHARIDES Monosaccharides are the simplest carbohydrates in that they cannot be hydrolyzed to smaller carbohydrates. They are aldehydes or ketones with two or more hydroxyl groups. If the carbonyl group is an aldehyde, the monosaccharide is an aldose. If the carbonyl group is a ketone, the monosaccharide is a ketose.

D - RIBULOSE D - FRUCTOSE

OXIDATION As noted above, sugars may be classified as reducing or non- reducing based on their reactivity with Tollens', Benedict's or Fehling's reagents. If a sugar is oxidized by these reagents it is called reducing, since the oxidant (Ag (+) or Cu (+2) ) is reduced in the reaction, as evidenced by formation of a silver mirror or precipitation of cuprous oxide. The Tollens' test is commonly used to detect aldehyde functions; and because of the facile interconversion of ketoses and aldoses under the basic conditions of this test, ketoses such as fructose also react and are classified as reducing sugars.

REDUCTION Sodium borohydride reduction of an aldose makes the ends of the resulting alditol chain identical, HOCH 2 (CHOH) n CH 2 OH, thereby accomplishing the same configurational change produced by oxidation to an aldaric acid. Derivatives of HOCH 2 (CHOH) n CHO HOBr Oxidation → HOCH 2 (CHOH) n CO 2 H an Aldonic Acid HNO 3 Oxidation → H 2 OC(CHOH) n CO 2 H an Aldaric Acid NaBH 4 Reduction → HOCH 2 (CHOH) n CH 2 OH an Alditol

OSAZONE FORMATION

CHAIN SHORTENING AND LENGTHENING

DISACCHARIDESDISACCHARIDES MALTOSE: 4-O-α-D-Glucopyranosyl-D-glucose (the beta- anomer is drawn)

CELLOBIOSE: 4-O-β-D-Glucopyranosyl-D-glucose (the beta-anomer is drawn)

LACTOSE, a disaccharide composed of one D-galactose molecule and one D-glucose molecule, occurs naturally in mammalian milk.

SUCROSE, also known as table sugar, is a common disaccharide. It is composed of two monosaccharides: D- glucose (left) and D-fructose (right).

STARCH α –amylose α –amylopectin

α –amylose α –amylopectin