The semiquinone (FADH·) can be formed by either reduction of FAD or oxidation of FADH2 by accepting or donating one electron and one proton, respectively. Some proteins, however, generate and maintain a superoxidized form of the flavin cofactor, the flavin-N(5)-oxide.
What is flavin made of?
Flavin (from Latin flavus, "yellow") is the common name for a group of organic compounds based on pteridine, formed by the tricyclic heterocycle isoalloxazine. The biochemical source is the vitamin riboflavin.
How is flavin adenine dinucleotide made?
Flavin adenine dinucleotide (FAD) is synthesized from riboflavin and two molecules of ATP. Riboflavin is phosphorylated by ATP to give riboflavin 5′-phosphate (also called flavin mononucleotide, FMN). FAD is then formed from FMN by the transfer of an AMP moiety from a second molecule of ATP.
