A form of cytochrome P-450 catalyzing lanosterol 14 alpha-demethylation (tentatively called "P-450(14)DM") was purified from microsomes of semi-anaerobically grown cells of Saccharomyces cerevisiae to gel electrophoretic homogeneity. An apparent monomeric Mr = 58,000 was estimated for the purified cytochrome by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Both optical and EPR spectra of oxidized P-450(14)DM are characteristic of low spin ferric heme proteins, and its reduced CO complex showed a Soret absorption peak at 447 nm. As in the case of hepatic microsomal cytochromes P-450, the ethyl isocyanide complex of reduced P-450(14)DM was in a pH-dependent equilibrium between two states having Soret peaks at 429 and 453 nm, the equilibrium being considerably shifted toward the 453-nm state. Oxidized P-450(14)DM was peculiar in that in its CD spectrum there was a negative shoulder at 425 nm and the 350- and 414-nm troughs possessed larger and relatively smaller [theta] values, respectively, than those reported for other low spin ferric cytochromes P-450. Lanosterol was the only compound which caused a Type I spectral change in oxidized P-450(14)DM. The lanosterol-induced low to high spin state change was, however, only slight even at saturating concentrations of the sterol, indicating that the lanosterol-P-450(14)DM adduct was in a spin state equilibrium.
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|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Gene Ontology Term||Gene Ontology Term ID||Qualifier||Aspect||Method||Evidence||Source||Assigned On||Reference||Annotation Extension|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Phenotype||Experiment Type||Experiment Type Category||Mutant Information||Strain Background||Chemical||Details||Reference|
|Evidence ID||Analyze ID||Regulator||Regulator Systematic Name||Target||Target Systematic Name||Experiment||Conditions||Strain||Source||Reference|