Biochemistry

Daily intake of folic acid for adults is 200 p. It increases with protein deficiency in the diet, hard physical labor, work with radioisotopes, anemia, infectious diseases and under the influence of certain medications. Sources. The main sources of folic acid are fresh vegetables (lettuce, cabbage, parsley, tomatoes, carrots, beets), as well as liver, kidneys, beef, egg yolk, cheese. A certain amount of folic acid is synthesized by microorganisms in the colon. Folic acid is easily destroyed by cooking foods, especially vegetables. It is lost about 90% by long cooking. Folic acid is better preserved in animal products. Biotin (Vitamin H). Biotin was first isolated in 1936 from an egg yolk. Structure and physicochemical properties. The biotin molecule contains an imidozole (A) and thiophene rings constituting its heterocyclic part and a side chain represented by valerianic acid. CH HC CH — CH — CH — CH-CH — COOH Biotin High biological activity is obtained from natural objects E - N- biotinillisin (biocytin), which includes biotin and lysine. Biotin is quite resistant to high temperatures and oxidation. It withstands sterilization at 120 0 C, as well as boiling in acidic and alkaline solutions. It is well soluble in water and alcohol. Biological role. It was established that biotin is necessary for the action of enzymes that catalyze the biosynthesis of organic compounds. He is involved in the formation of malonin-CoA from acetyl-CoA and carbonic acid during the biosynthesis of fatty acids, as well as in the synthesis of purine bases, in the formation of oxalacetic acid from pyruvic acid. Biotin is involved in the regulation of trophic activity of the nervous system, skin, and the metabolism of proteins, fats and carbohydrates. Biotin deficiency. At the beginning of biotin hypovitaminosis, peeling of the skin of the face, arms, legs, hair loss, nail damage is observed, then lethargy, drowsiness, nausea, loss of appetite, swelling of the tongue and atrophy of its 258