Kinetic properties of guinea pig liver microsomal NADPH-cytochrome P-450 reductase.
NADPH-cytochrome P-450 reductase was purified to apparent homogeneity from detergent-solubilized guinea pig liver microsomes. The reductase had a mol. wt of 78,000 and contained one mole each of FAD and FMN. Electron transfer activity to cytochrome c was optimal at a pH of 8.0 and an ionic strength of 0.43. The results of kinetic experiments were consistent with a ternary-complex mechanism for the interaction of the reductase with cytochrome c and NADPH. Km values for NADPH and cytochrome c were 3.1 and 26.7 microM, respectively. Inhibition by NADP+ and 2'-AMP was competitive with respect to NADPH; Ki values were 12.1 microM for NADP+ and 46.7 microM for 2'-AMP.
D000249:Adenosine Monophosphate / Q000494:pharmacology; D000818:Animals; D003574:Cytochrome c Group; D004579:Electron Transport; D006168:Guinea Pigs; D007700:Kinetics; D008297:Male; D008862:Microsomes, Liver / Q000201:enzymology*; D009249:NADP / Q000494:pharmacology; D009251:NADPH-Ferrihemoprotein Reductase / Q000037:antagonists & inhibitors / Q000378:metabolism*
D003574:Cytochrome c Group; D000249:Adenosine Monophosphate; D009249:NADP; D009251:NADPH-Ferrihemoprotein Reductase