Biochemistry

papillae ( “ varnish ” tongue), muscle pain, anemia. Biotin deficiency in the body can occur with intestinal diseases, decreased functions of the gastric glands, with prolonged treatment with antibiotics and sulfonamides that inhibit the intestinal microflora, using of a large number of raw egg proteins containing the albumin fraction, which is able to bind to biotin in the intestine and translate it into an indigestible form. Daily intake of biotin for adults is 150 p. Sources. By-productss (liver, heart), yeast, legumes, cauliflower, mushrooms, egg yolk, nuts are rich to biotins. Part of biotin is synthesized by colon microorganisms. Ascorbic acid (Vitamin C, antiscorbutic). The chemical nature of ascorbic acid was studied after its isolation in crystalline form from plant products. Vitamin C was discovered and cleaned by the Soviet chemist M.A. Bessonov in cabbage juice in 1922. The A.Saint-Gyorgy received a pure preparation from the adrenal glands in 1928. The drug was called ascorbic acid due to its anti- zingotic effect (from lat. scorbut - scurvy). Structure and physicochemical properties. Ascorbic acid is a white crystalline powder, sour in taste, readily soluble in water, worse soluble in alcohol and ether, stable in an acidic environment and unstable in neutral and alkaline environments. The structure of vitamin C was finally established due to its synthesis from a-xylose. HO HO ---- C H — C I HO — c I CH 2 OH Ascorbic acid C — H I CH 2 OH Dehydroascorbic acid According to the formula, ascorbic acid is an unsaturated compound that does not have a carboxyl group characteristic of acids. The presence of two enol groups located at the second and third carbon atoms determines the acidic properties and easy oxidation of vitamin C. This dienol group easily dissociates into free hydrogen, which gives the solution an acidic taste. Hydrogen is very easily bound with atmospheric oxygen. 259