[Effect of cytochrome b5 on the functional activity and conformational state of cytochrome P-450].
Microsomal cytochromes P-450 and b5 were shown to form mixed complexes with the association constant of 0.24 microM in water solution. Such complex formation stabilizes cytochrome P-450 in the catalytically active conformational state characterized by increased conformational rigidity and temperature stability. This stabilization results in acceleration of the cumene hydroperoxide-dependent oxidation of p-nitroanisol catalyzed by cytochrome P-450. The thermodynamic parameters of O-demethylation of p-nitroanisol catalyzed by cytochrome P-450 and mixed haemoprotein complexes measured in water solution and in a membrane-bound state were found to be different.
D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D003573:Cytochrome b Group / Q000378:metabolism*; D015786:Cytochromes b5; D007700:Kinetics; D046911:Macromolecular Substances; D010084:Oxidation-Reduction; D011487:Protein Conformation; D013816:Thermodynamics
D003573:Cytochrome b Group; D046911:Macromolecular Substances; D015786:Cytochromes b5; D003577:Cytochrome P-450 Enzyme System
Vliianie tsitokhroma b5 na funktsional'nuiu aktivnost' i konformatsionnoe sostoianie tsitokhroma P-450.