Substrate-inducible microsomal aryl hydroxylase in mammalian cell culture. II. Cellular responses during enzyme induction.
Substrate-inducible microsomal aryl hydroxylase in mammalian cell culture. II. Cellular responses during enzyme induction.
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哺乳动物细胞培养物中底物诱导的微粒体芳基羟化酶。
DOI：
10.1016/s0021-9258(18)94484-4
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发表时间：
1968
期刊：
影响因子：
--
通讯作者：
H. Gelboin
中科院分区：
文献类型：
--
作者：
D. Nebert;H. Gelboin
芳基羟化酶系统在仓鼠胎儿细胞培养物中是可诱导的。酶系统定位于105,000 ×gpellet（“微粒体部分”），对NADPH和分子O2有绝对要求，pH最适值为pH 7.5，对二价阳离子有部分要求。暴露在一氧化碳中会降低酶的活性。用乙二胺四乙酸酯或胰蛋白酶处理完全阻止酶活性。以苯并[a]芘为底物，羟化酶的km约为0.6µm。苯并[a]蒽、7,12-二甲基苯并[a]蒽、3-甲基胆蒽、二苯并[a，h]蒽和二苯并[a，c]蒽也是酶体系的底物。羟基化苯并[a]芘产品的分光光度荧光测定足够灵敏，每毫升可检测10−12摩尔，因此，在测量培养细胞的羟化酶活性方面具有很大的效用。这种哺乳动物细胞培养体系有利于研究微粒体酶诱导机制以及相关癌变、药物和类固醇代谢等领域的研究。
The aryl hydroxylase enzyme system is inducible in hamster fetus cell cultures. The enzyme system is localized in the 105,000 ×gpellet ("microsomal fraction"), has an absolute requirement for NADPH and molecular O2, a pH optimum of pH 7.5, and a partial requirement for divalent cations.Exposure to carbon monoxide reduces the enzyme activity. Treatment with ethylenediaminetetraacetate or trypsin completely prevents enzymatic activity. TheKmfor the hydroxylase is approximately 0.6 µm with benzo[a]pyrene as substrate. Benz[a]anthracene, 7,12-dimethylbenz[a]anthracene, 3-methylcholanthrene, dibenz[a,h]anthracene, and dibenz[a,c]anthracene are also substrates for the enzyme system.The spectrophotofluorometric determination of hydroxylated benzo[a]pyrene products is sufficiently sensitive to detect 10−12mole per ml and, hence, has great utility in measuring the hydroxylase activity of cells grown in culture. This mammalian cell culture system is advantageous for the study of the mechanism of microsomal enzyme induction and the related areas of carcinogenesis and drug and steroid metabolism.