Biochemistry

Structure and physicochemical properties. Vitamin B ]5 is a hygroscopic crystalline white powder, readily soluble in water, but not soluble in ether, chloroform and benzene, stable in an acidic environment. Pangamic acid is an ester of gluconic acid and dimethylglycine. H 3 C H H OH H \ Illi N - CH 2 - CO - О - CH 2 -- C - C - C - С -COOH / Illi H 3 C OHOHH OH Pangamic (NN- dimethylglycine -6- gluconic) acid Biological role. The mechanism of action of pangamic acid consists in the catalytic acceleration of methyl group transfer reactions (in particular, it provides the biosynthesis of choline, methionine, creatine phosphate). The presence of a gluconate residue in the molecule determines the ability of pangamic acid to stimulate glycogen synthesis in muscles and liver. It has a detoxifying property: it reduces the toxicity of sulfonamides and some antibiotics. Vitamin Bn increases the fat metabolism intensity, helps eliminate fat in liver. It activates the oxygen exchange in cells of tissues and organs. Daily intake not established; for therapeutic purposes, 100-300 mg / day are administered. Sources. Vitamin Bi 5 is found in plant seeds, yeast, rice bran, and liver. CONTROL QUESTIONS AND TASKS: 1. What are vitamins, how are they classified? 2. What do hypovitaminosis, avitaminosis, hypervitaminosis mean? 3. What substances have an anti-vitamin effect? 4. Tell us about the biological role of В vitamins, their chemical structure, daily intake and food sources. 5. In which biochemical reactions does ascorbic acid participate, what are its chemical structure, daily intake and food sources? 6. What fat-soluble vitamins are deficient and why? 7. Describe the biological role of fat- soluble vitamins, chemical structure, daily intake and food sources. 8. What compounds are vitamin-like compounds? What products are their sources? 9. What vitamins is part of coenzymes? 10. How to increase the vitamin value of food? 274