Effect of inhibitors of protein synthesis on rat liver spermidine N-acetyltransferase.
Effect of inhibitors of protein synthesis on rat liver spermidine N-acetyltransferase.
复制标题
蛋白质合成抑制剂对大鼠肝脏亚精胺N-乙酰转移酶的影响。
DOI：
10.1016/0304-4165(81)90028-3
复制
发表时间：
1981
期刊：
影响因子：
--
通讯作者：
Pegg,AE
中科院分区：
文献类型：
--
作者：
Matsui,I;Pegg,AE
在大鼠肝脏中产生的四氯化碳spermidineN 1-乙酰转移酶活性的增加完全防止同时治疗与蛋白质和核酸合成的抑制剂，这表明增加的结果从新的蛋白质的合成，而不是从一个神秘的无活性形式的酶的释放。四氯化碳处理后2小时放线菌酮也完全阻断了4小时后看到的亚精胺N1-乙酰转移酶的上升。这样的治疗完全防止了亚精胺的下降和上升腐胺在肝脏6小时后，四氯化碳确认的重要性，诱导的亚精胺N1-乙酰转移酶的亚精胺转化为腐胺。当放线菌酮给药的大鼠，其中亚精胺N1-乙酰转移酶的活性已被刺激的预先处理与四氯化碳或硫代乙酰胺，活性迅速丧失，表明该酶蛋白具有快速的周转率。硫代乙酰胺处理的大鼠中酶的半衰期为40分钟，而鸟氨酸脱羧酶的半衰期在四氯化碳处理的大鼠中，蛋白质降解速率降低，精脒N1-N2的半衰期延长。乙酰转移酶为155分钟，鸟氨酸脱羧酶为65分钟。看来参与腐胺和亚精胺的合成和相互转化的三种酶即，鸟氨酸脱羧酶、S-腺苷甲硫氨酸脱羧酶和亚精胺N1-乙酰转移酶具有快速的更新速率，并且多胺水平受这些酶的量的变化调节。
The increase in spermidineN1-acetyltransferase activity in rat liver produced by carbon tetrachloride was completely prevented by simultaneous treatment with inhibitors of protein and nucleic acid synthesis suggesting that the increase results from the synthesis of new protein rather than the release of the enzyme from a cryptic inactive form. Treatment with cycloheximide 2 h after carbon tetrachloride also completely blocked the rise in spermidineN1-acetyltransferase seen 4 h later. Such treatment completely prevented the fall in spermidine and rise in putrescine in the liver 6 h after carbon tetrachloride confirming the importance of the induction of spermidineN1-acetyltransferase in the conversion of spermidine into putrescine. When cycloheximide was administered to rats in which spermidineN1-acetyltransferase activity had been stimulated by prior treatment with carbon tetrachloride or thioacetamide, the activity was lost rapidly showing that the enzyme protein has a rapid rate of turnover. The half-life for the enzyme in thioacetamide-treated rats was 40 min, whereas the half-life for ornithine decarboxylase (which is well known to turn over very rapidly) was 27 min. In carbon tetrachloride-treated rats the rate of protein degradation was reduced and the half-life of spermidineN1-acetyltransferase was 155 min and that for ornithine decarboxylase was 65 min. It appears that three of the enzymes involved in the synthesis and interconversion of putrescine and spermidine namely, ornithine decarboxylase,S-adenosylmethionine decarboxylase and spermidineN1-acetyltransferase have rapid rates of turnover and that polyamine levels are regulated by changes in the amount of these enzymes.