Cytochrome b₅ reductase-cytochrome b₅ as an active P450 redox enzyme system in Phanerochaete chrysosporium: atypical properties and in vivo evidence of electron transfer capability to CYP63A2.

ABSTRACT: Two central redox enzyme systems exist to reduce eukaryotic P450 enzymes, the P450 oxidoreductase (POR) and the cyt b₅ reductase-cyt b₅. In fungi, limited information is available for the cyt b(5) reductase-cyt b(5) system. Here we characterized the kinetic mechanism of (cyt b₅r)-cyt b₅ redox system from the model white-rot fungus Phanerochaete chrysosporium (Pc) and made a quantitative comparison to the POR system. We determined that Pc-cyt b₅r followed a "ping-pong" mechanism and could directly reduce cytochrome c. However, unlike other cyt b₅ reductases, Pc-cyt b₅r lacked the typical ferricyanide reduction activity, a standard for cyt b₅ reductases. Through co-expression in yeast, we demonstrated that the Pc-cyt b₅r-cyt b₅ complex is capable of transferring electrons to Pc-P450 CYP63A2

SUBMITTER: Syed K 

PROVIDER: S-EPMC3119499 | biostudies-literature | 2011 May

REPOSITORIES: biostudies-literature