Kinetics of elementary steps in the cytochrome P-450 reaction sequence. VI. Model treatment of the NADPH-dependent first electron transfer reaction between cytochrome P-450 reductase and cytochrome P-450 LM2 in solution.
The NADPH-dependent reduction of P-450 LM2 has been studied both anaerobically and aerobically in solution state. The disintegration of the constitutive proteins was obtained by means of Triton N-101. At varied P-450 reductase/P-450 ratios two sets of reaction curves were treated by computer procedures. A general reaction mechanism of a modified Michaelis-Menten type could be evidenced. Rate determination in the overall reaction could be proved to be exerted by the electron transfer in the P-450 reductase/P-450 intermediate complex. This process is unresolved as yet. The significance of the solution state investigations is outlined with respect to the functional clusters in microsomes and liposomes, respectively. The physiologically relevant cluster reduction is supposed to follow similar kinetics based on a rapid protein exchange in the clusters.
D000332:Aerobiosis; D000693:Anaerobiosis; D000818:Animals; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D004579:Electron Transport; D007700:Kinetics; D008433:Mathematics; D008862:Microsomes, Liver / Q000378:metabolism*; D008954:Models, Biological; D009249:NADP / Q000378:metabolism; D009251:NADPH-Ferrihemoprotein Reductase / Q000378:metabolism*; D010084:Oxidation-Reduction; D011485:Protein Binding; D011817:Rabbits; D012996:Solutions
D012996:Solutions; D009249:NADP; D003577:Cytochrome P-450 Enzyme System; D009251:NADPH-Ferrihemoprotein Reductase