Catechol estrogen-forming enzyme of brain: demonstration of a cytochrome p450 monooxygenase.
Catechol estrogen-forming enzyme of brain: demonstration of a cytochrome p450 monooxygenase.
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脑儿茶酚雌激素形成酶：细胞色素 p450 单加氧酶的演示。
作者：
S. Paul;J. Axelrod;E. Diliberto
一种儿茶酚雌激素形成酶已被证明在大鼠脑微粒体中使用灵敏的放射酶测定。该方法基于相对不稳定的儿茶酚雌激素转化为其稳定的O-甲基化衍生物。通过采用高比活性的甲基供体（S-腺苷-L-[甲基-3H]甲硫氨酸）、儿茶酚-O-甲基转移酶（COMT）的部分纯化制剂和选择性溶剂萃取，该方法已被证明是极其灵敏的。通过在几种溶剂系统中对O-甲基化产物进行薄层色谱分析，确定了试验的专属性，并通过色谱产物的质谱分析进一步确证。使用还原的NADP，大鼠脑的酶活性是最佳的，并且被P450依赖性混合功能氧化酶的众所周知的抑制剂CO和SKF-525 A抑制。亚细胞分布，辅因子的要求，和各种抑制剂的影响强烈表明，酶活性的B。
A catechol estrogen-forming enzyme has been demonstrated in rat brain microsomes using a sensitive radioenzymatic assay. This method is based on conversion of the relatively labile catechol estrogens to their stable O-methylated derivatives. By employing a methyl donor of high specific activity (S-adenosyl-L-[methyl-3H]methionine), a partially purified preparation of catechol- O-methyltransferase (COMT), and selective solvent extraction this method has proven to be extremely sensitive. The specificity of the assay was established by subjecting the O-methylated product to thin layer chromatography in several solvent systems and further confirmed by mass spectral analysis of the chromatographed product. The enzymatic activity of rat brain is optimal using reduced NADP and is inhibited by well known inhibitors of P450-dependent mixed function oxidases, CO and SKF- 525A. The subcellular distribution, cofactor requirements, and the effects of various inhibitors strongly suggest that the enzymatic activity of b...