Yoshida Y, Aoyama Y, Nishino T, Katsuki H, Maitra U S, Mohan V P, Sprinson D B
Biochem Biophys Res Commun. 1985 Mar 15;127(2):623-8. doi: 10.1016/s0006-291x(85)80206-0.
An altered cytochrome P-450 (SG1 P-450) was partially purified from Saccharomyces cerevisiae mutant SG1 which is defective in lanosterol 14 alpha-demethylation. Oxidized SG1 P-450 showed a Soret peak at 422 nm and the alpha peak was lower than the beta peak. This spectrum was considerably different from those of known low-spin P-450s, indicating a unique ligand structure of SG1 P-450. The absorption spectrum of ferric SG1 P-450 was superimposable on that of the imidazole complex of ferric P-450, suggesting the presence of a nitrogenous ligand such as histidine of the apoprotein at the 6th coordination position. SG1 P-450 was immunochemically indistinguishable from cytochrome P-450 of S. cerevisiae catalyzing lanosterol 14 alpha-demethylation (P-45014DM) but had no lanosterol 14 alpha-demethylase activity.
从酿酒酵母突变体SG1中部分纯化出一种改变的细胞色素P-450（SG1 P-450），该突变体在羊毛甾醇14α-去甲基化方面存在缺陷。氧化态的SG1 P-450在422 nm处显示出一个Soret峰，且α峰低于β峰。该光谱与已知的低自旋P-450的光谱有很大不同，表明SG1 P-450具有独特的配体结构。铁离子态SG1 P-450的吸收光谱与铁离子态P-450的咪唑配合物的吸收光谱重叠，这表明在第六配位位置存在一种含氮配体，如脱辅基蛋白的组氨酸。SG1 P-450在免疫化学上与催化羊毛甾醇14α-去甲基化的酿酒酵母细胞色素P-450（P-45014DM）无法区分，但没有羊毛甾醇14α-去甲基酶活性。
