亚硒酸盐：大鼠肝脏DNA甲基化酶的有效抑制剂。

Selenite: a good inhibitor of rat-liver DNA methylase.

作者信息

Cox R

出版信息

Biochem Int. 1985 Jan;10(1):63-9.

Abstract

DNA methylase from rat liver was partially purified through a DEAE sephacel column and characterized in an in vitro assay with respect to time, protein, DNA and S-adenosylmethionine curves. The Km for S-adenosylmethionine was 2.5 microM. Sodium selenium inhibited the methylation of DNA in a dose dependent fashion when added to the assay. It was also demonstrated that selenite non-competitively inhibits rat-liver DNA methylase with a Ki of 6.7 microM. Dithiothreitol had no effect on selenite inhibition and increasing amounts of DNA did not alter the inhibition. However, increasing amounts of protein overcame the inhibition, suggesting that selenite is reacting with the DNA methylase protein. DNA methylase isolated from selenite treated animals had only 43% of the activity as enzyme from control rats. It appears that selenite is a good inhibitor of DNA methylase.

摘要

大鼠肝脏中的DNA甲基化酶通过DEAE葡聚糖凝胶柱进行了部分纯化，并在体外试验中对其时间、蛋白质、DNA和S-腺苷甲硫氨酸曲线进行了表征。S-腺苷甲硫氨酸的Km为2.5微摩尔。在试验中添加亚硒酸钠时，它以剂量依赖的方式抑制DNA的甲基化。还证明亚硒酸盐以非竞争性方式抑制大鼠肝脏DNA甲基化酶，其Ki为6.7微摩尔。二硫苏糖醇对亚硒酸盐的抑制作用没有影响，并且DNA量的增加不会改变抑制作用。然而，蛋白质数量的增加克服了这种抑制作用，这表明亚硒酸盐正在与DNA甲基化酶蛋白发生反应。从经亚硒酸盐处理的动物中分离出的DNA甲基化酶的活性仅为对照大鼠酶活性的43%。看来亚硒酸盐是一种良好的DNA甲基化酶抑制剂。