Whitlock J P, Miller H, Gelboin H V
J Cell Biol. 1974 Oct;63(1):136-45. doi: 10.1083/jcb.63.1.136.
In the Reuber (H35) hepatoma cell strain, microsomal aryl hydrocarbon (benzo[a]pyrene) hydroxylase is induced 25-fold by the polycyclic hydrocarbon benz[a]anthracene but is not induced by the steroid hormone dexamethasone. Soluble tyrosine aminotransferase is induced sixfold by dexamethasone and twofold by benz[a]anthracene. Each enzyme requires similar inducer concentrations for induction, and their induction kinetics are similar. The induction of each enzyme requires RNA and protein synthesis; in each case the transcriptional and translational steps can occur independently. The two induction systems are differentially sensitive to inhibitors of macromolecular synthesis. Simultaneous exposure to both inducers produces increases in both enzyme activities that are greater than those produced by either inducer alone. Each inducer acts at a pretranslational level to produce this synergistic effect. The results suggest that the requirements for macromolecular synthesis are similar for the induction of each enzyme, but that the turnover of enzyme-specific macromolecules may differ for each.
在鲁伯(H35)肝癌细胞株中,微粒体芳烃(苯并[a]芘)羟化酶可被多环烃苯并[a]蒽诱导25倍,但不被甾体激素地塞米松诱导。可溶性酪氨酸转氨酶可被地塞米松诱导6倍,被苯并[a]蒽诱导2倍。每种酶的诱导都需要相似的诱导剂浓度,且它们的诱导动力学相似。每种酶的诱导都需要RNA和蛋白质合成;在每种情况下,转录和翻译步骤都可以独立发生。这两种诱导系统对大分子合成抑制剂的敏感性不同。同时暴露于两种诱导剂会使两种酶的活性增加,且大于单独使用任何一种诱导剂所产生的增加。每种诱导剂都在翻译前水平起作用以产生这种协同效应。结果表明,每种酶诱导对大分子合成的要求相似,但每种酶特异性大分子的周转可能不同。