[Nonenzymatic reduction of methemoglobin by free radical forms of NADH and riboflavin].
Nonenzymatic reduction of methemoglobin (met-Hb) is effectively catalyzed by NADH and riboflavin (RF). At low concentrations of met-Hb the EPR spectra of the ternary complex are characterized by an increased, whereas those at high met-Hb concentrations--by a decreased intensity of the RF semiquinone signal, which suggests that the met Hb reduction by a Leu-form of RF proceeds at a higher rate than that by the RF semiquinone radical. Riboflavin also accelerates the met-Hb reduction by a NADH-Fe2+ or NADH-Fe(2+)-EDTA mixture. It was found that the rate of met-Hb reduction by the organic radical increases in the following order: NAD. < RF H. < RF H2.
Sepuro
I I
II
Oparin
D A
DA
Kuznetsova
A S
AS
Silinevich
I I
II
D002384:Catalysis; D004578:Electron Spin Resonance Spectroscopy; D004798:Enzymes / Q000378:metabolism; D005609:Free Radicals; D006801:Humans; D008706:Methemoglobin / Q000378:metabolism*; D009243:NAD / Q000378:metabolism*; D010084:Oxidation-Reduction; D012256:Riboflavin / Q000378:metabolism*
D004798:Enzymes; D005609:Free Radicals; D009243:NAD; D008706:Methemoglobin; D012256:Riboflavin
Neénzimaticheskoe vosstanovlenie metgemoglobina svobodnoradikal'nymi formami NADH i riboflavina.