Effect of 1,3-diaminopropane on ornithine decarboxylase enzyme protein in thioacetamide-treated rat liver.
Effect of 1,3-diaminopropane on ornithine decarboxylase enzyme protein in thioacetamide-treated rat liver.
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1,3-二氨基丙烷对硫代乙酰胺处理的大鼠肝脏中鸟氨酸脱羧酶蛋白的影响。
DOI：
10.1042/bj2160701
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发表时间：
1983
期刊：
影响因子：
--
通讯作者：
Pegg,AE
中科院分区：
文献类型：
--
作者：
Seely,JE;Pegg,AE
用放射免疫法研究了鸟氨酸脱羧酶在大鼠肝脏中的调节作用。所使用的抗血清可与小鼠、人或大鼠细胞中的鸟氨酸脱羧酶反应。在给药1,3-二氨基丙烷后的不同时间，测定了硫代乙酰胺处理大鼠肝脏鸟氨酸脱羧酶酶活性和酶蛋白（用放射免疫法测定）。1,3-二氨基丙烷处理后，酶活性迅速下降，酶蛋白含量也迅速下降，但酶活性的消失略早于免疫反应蛋白的丧失。环己亚胺处理后酶蛋白的损失也迅速发生，但明显慢于1,3-二氨基丙烷处理。同时注射1,3-二氨基丙烷和环己亚胺时，酶活性和酶蛋白的消失速度与单独注射环己亚胺时相同。这些结果表明，1,3-二氨基丙烷处理后酶活性的快速损失主要是由于酶蛋白的损失，蛋白质的合成需要使1,3-二氨基丙烷充分发挥其作用。鸟氨酸脱羧酶的一种大分子抑制剂被称为抗酶，在1,3-二氨基丙烷的作用下被诱导，但我们的研究结果表明，酶活性的丧失不是由于无活性鸟氨酸脱羧酶-抗酶复合物的积累。可能是抗酶增强了酶蛋白的降解。对照实验表明，所使用的抗血清可以检测到肝脏中存在的任何无活性的抗酶-鸟氨酸脱羧酶复合物，因为在体外向鸟氨酸脱羧酶中添加抗酶并不影响我们放射免疫测定中检测到的鸟氨酸脱羧酶的数量。抗（鸟氨酸脱羧酶）抗体可能用于纯化抗酶，因为抗酶-鸟氨酸脱羧酶复合物可以免疫沉淀，并且在0.3 M-NaCl下从沉淀中释放出抗酶。
A radioimmunoassay for ornithine decarboxylase was used to study the regulation of this enzyme in rat liver. The antiserum used reacts with ornithine decarboxylase from mouse, human or rat cells. Rat liver ornithine decarboxylase enzyme activity and enzyme protein (as determined by radioimmunoassay) were measured in thioacetamide-treated rats at various times after administration of 1,3-diaminopropane. Enzyme activity declined rapidly after 1,3-diaminopropane treatment as did the amount of enzyme protein, although the disappearance of enzyme activity slightly preceded the loss of immunoreactive protein. The loss of enzyme protein after cycloheximide treatment also occurred rapidly, but was significantly slower than that seen with 1,3-diaminopropane. When 1,3-diaminopropane and cycloheximide were injected simultaneously, the rate of disappearance of enzyme activity and enzyme protein was the same as that seen with cycloheximide alone. These results show that the rapid loss in enzyme activity after 1,3-diaminopropane treatment is primarily due to a loss in enzyme protein and that protein synthesis is needed in order for 1,3-diaminopropane to exert its full effect. A macromolecular inhibitor of ornithine decarboxylase that has been termed antizyme is induced in response to 1,3-diaminopropane, but our results indicate that the loss of enzyme activity is not due to the accumulation of inactive ornithine decarboxylase-antizyme complexes. It is possible that the antizyme enhances the degradation of the enzyme protein. Control experiments demonstrated that the antiserum used would have detected any inactive antizyme-ornithine decarboxylase complexes present in liver since addition of antizyme to ornithine decarboxylase in vitro did not affect the amount of ornithine decarboxylase detected in our radioimmunoassay. Anti-(ornithine decarboxylase) antibodies may be useful in the purification of antizyme since the antizyme-ornithine decarboxylase complex can be immunoprecipitated, and antizyme released from the precipitate with 0.3 M-NaCl.