[Chemical and functional properties of flavin coenzymes].
The yellow-colored compounds with the basic structural frame work of 7,8-dimethyl-10-alkylisoalloxazine are generally termed as flavins. The 10-ribityl derivative, riboflavin, is the most abundant flavin found in nature and is known as vitamin B2. Riboflavin is a precursor of the flavocoenzymes, FMN (flavin mononucleotide) and FAD (flavin adenine dinucleotide) which function as prosthetic groups of flavocoenzymes. While flavocoenzymes are usually bound noncovalently to apoproteins of flavoenzymes, covalently-bound flavocoenzymes also occur in nature, though much less often. Flavin molecules can exist in three different redox states, i.e., oxidized, one-electron reduced and two-electron reduced states, and therefore can participate in redox reactions as either one- or two-electron mediator, making the flavoenzymes extremely versatile in terms of substrate and type of reactions catalyzed. We classified flavoenzymes according to the electron-transfer process in their reductive and oxidative half-reactions and the mechanism of each class of flavoenzymes is discussed in detail.
Setoyama
C
C
Department of Biochemistry, Kumamoto University School of Medicine.
Miura
R
R
D003067:Coenzymes / Q000737:chemistry; D005486:Flavin Mononucleotide / Q000737:chemistry; D005182:Flavin-Adenine Dinucleotide / Q000737:chemistry; D005415:Flavins / Q000737:chemistry*; D009243:NAD / Q000737:chemistry; D010084:Oxidation-Reduction
D003067:Coenzymes; D005415:Flavins; D009243:NAD; D005182:Flavin-Adenine Dinucleotide; D005486:Flavin Mononucleotide