title: Rat brain NADPH-dependent diaphorase. A possible relationship to cytochrome P450 reductase.
abstract: An enzyme (NADPH-dependent diaphorase) present in rat brain microsomes has been solubilised and shown to utilise both nitrobluetetrazolium and cytochrome c as electron acceptors, when reduced by NADPH. The kinetics of the enzyme have been determined using cytochrome c (Km = 1.3 microM), NADPH (Km = 1.4 microM) and the Vmax (4.7 nmol/min/mg solubilised microsome protein). The subunit Mr is approximately 73,000 D and that of the native enzyme is 170,000-180,000 D, indicating that the enzyme is probably a dimer. Evidence is also provided to show that the enzyme is a flavoprotein, and that it has equimolar amounts of FAD and FMN with respect to the subunit concentration. It seems a possibility that the rat brain diaphorase enzyme may be cytochrome P450 reductase, EC 1.6.2.4.
mesh_terms: D000818:Animals; D001921:Brain / Q000201:enzymology* / Q000648:ultrastructure; D005486:Flavin Mononucleotide / Q000378:metabolism; D005182:Flavin-Adenine Dinucleotide / Q000378:metabolism; D007700:Kinetics; D008433:Mathematics; D008861:Microsomes / Q000201:enzymology; D008970:Molecular Weight; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism*; D009252:NADPH Dehydrogenase / Q000378:metabolism*; D009251:NADPH-Ferrihemoprotein Reductase / Q000378:metabolism*; D051381:Rats
chemical_list: D005182:Flavin-Adenine Dinucleotide; D005486:Flavin Mononucleotide; D009247:NADH, NADPH Oxidoreductases; D009251:NADPH-Ferrihemoprotein Reductase; D009252:NADPH Dehydrogenase