riboflavin(redirected from Vitamin B-2)
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, any one of a group of relatively small organic molecules required for the catalytic function of certain enzymes. A coenzyme may either be attached by covalent bonds to a particular enzyme or exist freely in solution, but in either case it participates intimately in
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group of organic substances that are required in the diet of humans and animals for normal growth, maintenance of life, and normal reproduction. Vitamins act as catalysts; very often either the vitamins themselves are coenzymes, or they form integral parts of coenzymes.
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(also lactoflavin and Vitamin B2), an important and biologically active substance that is a derivative of the heterocyclic compound isoalloxazine attached to ribitol, a multi-atomic alcohol.
Riboflavin is widely distributed in the cells of microorganisms, plants, and animals, although animals are unable to bio-synthesize riboflavin and must obtain it with food. The biological role of riboflavin is determined by the presence of its derivatives—flavin mononucleotide (FMN) and flavin-adenine dinucleotide (FAD)—in a series of oxidation and reducing enzymes (flavoproteins) during electron transfer reactions and the metabolism of amino acids and other vitamins.
In man, many diseases are accompanied by disorders of the metabolism of riboflavin. A deficiency of riboflavin results in skin lesions and vision disorders, while an acute insufficiency leads to the development of a comatose state. Riboflavin is present in most food products, including brewer’s yeast, egg yolk, beef liver, and milk products. It is also synthesized by intestinal bacteria.
The structure of riboflavin was independently established in 1935 through chemical synthesis both by R. Kuhn and P. Karrer. Riboflavin is used in medicine as a vitamin preparation.