STRUCTURE AND REGULATION OF CYTOCHROMES P-450

将对类固醇生成细胞色素P-450进行研究 继续进一步刻画了这些活跃的 六种合成类固醇的细胞色素P-450(芳香酶，11B- 羟基酶，C27侧链裂解，21-羟基酶，17a- 羟基酶和C21侧链断裂)。定性将 通过使用溴乙酰氧基的活性部位亲和标记来实现- 与这些化合物的活性部位特异结合的类固醇 酵素。这些酶目前正受到 微测序和基因克隆相结合的方法； 这些程序将继续进行，直到完成序列 对这些猪酶进行测定；这一信息是至关重要的 对活性部位标记的解释。组织的组织 类固醇合成蛋白(P-450、P-450还原酶、细胞色素b5) 在猪和大鼠的睾丸和肾上腺微粒子中 研究鉴定一种孕烯醇酮结合蛋白，以交叉- 将细胞色素P-450连接到相邻的微粒体蛋白并连接到 用免疫电子方法确定这些蛋白质的排列 显微镜。这些对微体蛋白的研究将会利用 与上述抗体发生交叉反应的特性良好的抗体 猪和大鼠微粒体内的蛋白质。

Investigation of steroidogenic cytochromes P-450 will be continued with further characterization of the active sties of the six steroidogenic cytochromes P-450 (aromatase, 11B- hydroxylase, C27 side-chain cleavage, 21-hydroxylase, 17a- hydroxylase and C21 side-chain cleavage). Characterization will be achieved by active site-affinity-labelling using bromoacetoxy- steroids that bind specifically to the active sites of these enzymes. The enzymes are presently being subjected to the combined approaches of microsequencing and genetic cloning; these procedures will be continued until the complete sequences of these porcine enzymes are determined; this information is vital to interpretation of active site labelling. The organization of steroidogenic proteins (P-450, P-450 reductase, cytochrome b5) within testicular and adrenal microsomes from pig and rat will be studied to characterize a pregnenolone-binding protein, to cross- link cytochromes P-450 to adjacent microsomal proteins and to determine the arrangement of these proteins by immunoelectron microscopy. These studies of microsomal proteins will make use of well characterized antibodies that cross-react with the above proteins from pig and rat microsomes.