Vitamin B2,Riboflavin is moderately soluble in water (10–13 mg/dl) and ethanol but insoluble in ether, chloroform, and acetone. It is soluble but unstable under alkaline conditions.The catalytic functions of riboflavin are carried out primarily at positions N-1, N-5, and C-4 of the isoalloxazine nucleus. In addition, the methyl group at C-8 participates in covalent bonding with enzyme proteins. The flavin coenzymes are highly versatile redox cofactors because they can participate in either one- or two electron redox reactions.Riboflavin antagonists include analogs of the isoalloxazine ring (e.g., diethylri boflavin, dichlororiboflavin) and the ribityl side chain (e.g., d-araboflavin, d-galactoflavin, 7-ethylriboflavin).Nutritional factor found in milk, eggs, malted barley, liver, kidney, heart, leafy vegetables. Richest natural source is yeast. Minute amounts present in all plant and animal cells. Vitamin (enzyme cofactor).
