Biodiversity of the P450 catalytic cycle: yeast cytochrome b5/NADH cytochrome b5 reductase complex efficiently drives the entire sterol 14‐demethylation (CYP51) reaction
Open Access
- 30 November 1999
- journal article
- Published by Wiley in FEBS Letters
- Vol. 462 (3) , 283-288
- https://doi.org/10.1016/s0014-5793(99)01548-3
Abstract
The widely accepted catalytic cycle of cytochromes P450 (CYP) involves the electron transfer from NADPH cytochrome P450 reductase (CPR), with a potential for second electron donation from the microsomal cytochrome b 5/NADH cytochrome b 5 reductase system. The latter system only supported CYP reactions inefficiently. Using purified proteins including Candida albicans CYP51 and yeast NADPH cytochrome P450 reductase, cytochrome b 5 and NADH cytochrome b 5 reductase, we show here that fungal CYP51 mediated sterol 14α‐demethylation can be wholly and efficiently supported by the cytochrome b 5/NADH cytochrome b 5 reductase electron transport system. This alternative catalytic cycle, where both the first and second electrons were donated via the NADH cytochrome b 5 electron transport system, can account for the continued ergosterol production seen in yeast strains containing a disruption of the gene encoding CPR.Keywords
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