BIOCHEMICAL CHARACTERISTICS OF INSECT MICROSOMES - N-DEMETHYLATION AND O-DEMETHYLATION
BIOCHEMICAL CHARACTERISTICS OF INSECT MICROSOMES - N-DEMETHYLATION AND O-DEMETHYLATION
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DOI：
10.1016/0006-2952(71)90285-1
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发表时间：
1971-01-01
影响因子：
5.8
通讯作者：
HODGSON, E
中科院分区：
文献类型：
--
作者：
HANSEN, LG;HODGSON, E
本文研究了家蝇成虫微粒体对N，N-二甲基-对硝基苯酚氨基甲酸酯的N-脱甲基作用和对硝基苯甲醚的O-脱甲基作用。雄蝇的脱甲基活性在羽化后4d达到最大值，而雌蝇的最大活性在羽化后7- 9d才达到。粉杵匀浆比搅拌器匀浆更有效。发现0.20 M磷酸钾缓冲液（pH7.8）上级用于制备微粒体的所有其他试验培养基。很明显，制备介质的离子强度比摩尔浓度或pH值更重要，以获得最大的N-和O-脱甲基活性的微粒体。在随后的温育过程中，需要0.5 - 1.0%的牛血清白蛋白才能达到最大活性，O-和N-去甲基化的最适pH值在7.7 - 8.1之间，加入NADPH或使用生成系统，两种反应在30-33 ℃时活性最大。pNA的表观Km为9.0 ± 0.4 × 10− 5 M，DpNC的表观Km为4.0 ± 1.6 × 10− 4 M。
TheN-demethylation ofN,N-dimethyl-p-nitrophenol carbamate and theO-demethylation ofp-nitroanisole by the microsomes from housefly abdomens were studied.Demethylation activity of male flies rises to a maximum at 4 days after emergence, while the maximum activity of females is not realized until 7–9 days after emergence.Homogenization with a teflon pestle is more effective than a blender, and 0.20 M potassium phosphate buffer (pH 7.8) was found to be superior to all other media tested for the preparation of the microsomes. It was apparent that the ionic strength of the preparative medium is more important than either molarity or pH for obtaining microsomes of maximumN- andO-demethylating activity. During the subsequent incubation, 0.5 to 1.0% bovine serum albumin is required for maximum activity.The pH optimum for bothO- andN-demethylation is between 7.7 and 8.1 with added NADPH or with the generating system, and both reactions show the greatest activity at 30–33°. The apparentKmfor pNA is 9.0 ± 0.4 × 10−5M and that for DpNC is 4.0 ± 1.6 × 10−4M.