Vickery L, Salmon A, Sauer K
Biochim Biophys Acta. 1975 Mar 28;386(1):87-98. doi: 10.1016/0005-2795(75)90249-4.
Magnetic circular dichroism spectra are reported for the visible and near ultraviolet spectral regions of liver microsomes from dimethylbenzanthracene-treated rats. The sequential addition of NADH, dithionite, and carbon monoxide enables us to determine contributions to the magnetic circular dichroism by cytochromes b-5 and P-450, which dominate the spectra. The magnetic circular dichroism of the microsomal preparation is compared with that of purified oxidized and reduced cytochrome -b-5 from pig liver and with the camphor-complexed and camphor-free oxidized, reduced, and reduced carbonmonoxy cytochrome P-450-cam from Pseudomonas putida. The magnetic circular dichroism spectra of the membrane bound cytochrome -b-5 are similar to those of the purified protein, indicating that little or no alteration in the environment of the heme occurs during the isolation procedure. The soluble bacterial cytochrome P-450 also appears to be a suitable model for microsomal P-450, although differences in the magnetic circular dichroism intensity are observed for the two enzymes. No effect of dimethylbenzanthracene on the magnetic circular dichroism spectra of induced compared to control rat microsomes could be observed.
报道了经二甲基苯并蒽处理的大鼠肝脏微粒体在可见光和近紫外光谱区域的磁圆二色光谱。依次加入还原型辅酶Ⅰ、连二亚硫酸盐和一氧化碳，使我们能够确定细胞色素b-5和P-450对磁圆二色性的贡献，这两种物质在光谱中占主导地位。将微粒体制剂的磁圆二色性与猪肝纯化的氧化型和还原型细胞色素b-5以及恶臭假单胞菌的樟脑复合和无樟脑的氧化型、还原型和还原型一氧化碳细胞色素P-450-cam的磁圆二色性进行了比较。膜结合细胞色素b-5的磁圆二色光谱与纯化蛋白的光谱相似，表明在分离过程中血红素环境几乎没有改变。可溶性细菌细胞色素P-450似乎也是微粒体P-450的合适模型，尽管观察到这两种酶在磁圆二色性强度上存在差异。与对照大鼠微粒体相比，未观察到二甲基苯并蒽对诱导的磁圆二色光谱有影响。
