Riboflavin

Riboflavin (vitamin B₂) is part of the vitamin B group. It is the central component of the cofactors FAD and FMN and as such required for a variety of flavoprotein enzyme reactions including activation of other vitamins. It was formerly known as vitamin G.

As a chemical compound, riboflavin is a yellow-orange solid substance with poor solubility in water compared to other B vitamins. Visually, it imparts color to vitamin supplements (and bright yellow color to the urine of persons taking a lot of it).

The name "riboflavin" comes from "ribose" (the sugar whose reduced form, ribitol, forms part of its structure) and "flavin", the ring-moiety which imparts the yellow color to the oxidized molecule (from Latin flavus, "yellow"). The reduced form, which occurs in metabolism along with the oxidized form, is colorless.

Function

Vitamins are small chemical compounds that humans (and other animals) cannot synthesize, but instead are absorbed from plant and animal foods. Riboflavin functions as a coenzyme, meaning that it is required for enzymes (proteins) to perform normal physiological actions. Specifically, the active forms or riboflavin Flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD) function as cofactors for a variety of flavoproteine enzyme reactions: