Mechanism of cytochrome P450 reductase from the house fly: evidence for an FMN semiquinone as electron donor

FEBS Letters

Feyereisen, René¹  Murataliev, Marat B¹ 

[1] Department of Entomology and Center for Toxicology, University of Arizona, Forbes 410, P.O. Box 210036, Tucson, AZ 85721-0036, USA

关键词: Cytochrome P450 reductase;    Flavoprotein;    Flavin semiquinone;    Catalytic mechanism;    CYP6A1;    cytochrome P450 6A1;    P450 reductase;    NADPH-cytochrome P450 reductase;    P450BM3;    cytochrome P450BM3;    isolated from Bacillus megaterium;    PEI-cellulose;    polyethyleneimine-impregnated cellulose;   

DOI  :  10.1016/S0014-5793(99)00723-1

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The interaction of recombinant house fly (Musca domestica) P450 reductase with NADPH and the role of the FMN semiquinone in reducing cytochrome c have been investigated. House fly P450 reductase can rapidly oxidize only one molecule of NADPH, whereas the rate of oxidation of a second molecule of NADPH is too slow to account for the observed rates of catalysis. This demonstrates that house fly P450 reductase does not require a priming reaction with NADPH for catalysis. Kinetics of cytochrome c reduction and EPR spectroscopy revealed that the enzyme forms two types of neutral FMN semiquinone. One serves as the catalytic intermediate of cytochrome c reduction, and another one is an ‘air-stable’ semiquinone, which reduces cytochrome c 3000 times more slowly. The results show that the reduction state of the house fly P450 reductase during catalysis cycles in a 0-2-1-0 sequence.

【 授权许可】

Unknown