FADH is the reduced form of flavin adenine dinucleotide (FAD). FAD is synthesized from riboflavin and two molecules of ATP. Riboflavin is phosphorylated by ATP to give riboflavin 5-phosphate (FMN). FAD is then formed from FMN by the transfer of an AMP moiety from a second molecule of ATP. FADH is generated in each round of fatty acid oxidation, and the fatty acyl chain is shortened by two carbon atoms as a result of these reactions; because oxidation is on the beta carbon, this series of reactions is called the beta-oxidation pathway. In the citric acid cycle, FADH is involved in the harvesting of high-energy electrons from carbon fuels; the citric acid cycle itself neither generates a large amount of ATP nor includes oxygen as a reactant. Instead, the citric acid cycle removes electrons from acetyl CoA and uses these electrons to form FADH.
Belongs to the class of organic compounds known as flavin nucleotides. These are nucleotides containing a flavin moiety. Flavin is a compound that contains the tricyclic isoalloxazine ring system, which bears 2 oxo groups at the 2- and 4-positions.
Kavakli I Halil; Sancar Aziz Analysis of the role of intraprotein electron transfer in photoreactivation by DNA photolyase in vivo. Biochemistry (2004), 43(48), 15103-10.
