/buy"euh tin/, n. Biochem.a crystalline, water-soluble vitamin, C10H16O3N2S, of the vitamin B complex, that is present in all living cells and functions as a growth factor and as a catalyst in carboxylation reactions. Also called vitamin H.
* * *Organic compound, part of the vitamin B complex, essential for growth and well-being in animals and some microorganisms.A carboxylic acid with two rings in its structure, it includes nitrogen and sulfur atoms as well as carbon, hydrogen, and oxygen. It functions in the formation and metabolism of fats and carbohydrates. It is widely distributed in nature and is especially abundant in egg yolk, beef liver, and yeast. A biotin deficiency can be induced by consuming large amounts of raw egg white, which contains a protein (avidin) that combines with biotin and makes it unavailable. Biotin is needed to synthesize fatty acids and convert amino acids to glucose in the body.
* * *water-soluble, nitrogen-containing acid essential for growth and well-being in animals and some microorganisms. Biotin is a member of the B complex (vitamin B complex) of vitamins (vitamin). It functions in the formation and metabolism of fats and carbohydrates. A relatively stable substance, it is widely distributed in nature and is especially abundant in egg yolk, beef liver, and yeast.Biotin was first identified as a nutritive requirement of yeast. Originally called vitamin H, it was isolated in pure form in 1935; its structure was established in 1942, after it had been shown to be required by animals. Evidence for the necessity of biotin appeared with the discovery in 1927 that the addition of uncooked egg white to a diet that is otherwise adequate produces toxicity and disease. This is because egg white contains a specific protein, avidin, that combines with biotin and thus prevents its absorption. In practice, biotin deficiency results only from the prolonged consumption of an exceptionally large number of uncooked egg whites; symptoms include dermatitis and hair loss.
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