Kresze G B, Steber L
Eur J Biochem. 1979 Apr;95(3):569-78. doi: 10.1111/j.1432-1033.1979.tb12998.x.
Mammalian pyruvate dehydrogenase multienzyme complex is inactivated when treated with a leupeptin-sensitive enzyme (termed 'inactivase') obtained from rat liver lysosomes. However, the inactivation of the overall reaction does not affect any of the component activities of the enzyme complex. By several methods it is demonstrated that treatment with the inactivase provokes the disassembly of the complex into its constituent enzyme components which, though being enzymatically active when assayed separately, are unable to catalyze the coordinated reaction sequence of pyruvate oxidation. The dissociation occurs as a consequence of limited proteolysis of the lipoate acetyltransferase core of the multienzyme complex. Isolated nicked acetyltransferase retains its complete enzymatic activity and behaves as a high-molecular-weight aggregate. The lipoamide dehydrogenase and pyruvate dehydrogenase components, however, are not cleaved by the inactivase.
当用从大鼠肝脏溶酶体中获得的一种亮抑酶肽敏感酶（称为“失活酶”）处理时，哺乳动物丙酮酸脱氢酶多酶复合物会失活。然而，整体反应的失活并不影响酶复合物的任何组成活性。通过几种方法证明，用失活酶处理会促使复合物分解成其组成酶成分，这些成分虽然在单独测定时具有酶活性，但无法催化丙酮酸氧化的协同反应序列。这种解离是多酶复合物硫辛酰胺乙酰转移酶核心有限蛋白水解的结果。分离出的带切口的乙酰转移酶保留其完整的酶活性，并表现为高分子量聚集体。然而，硫辛酰胺脱氢酶和丙酮酸脱氢酶成分不会被失活酶切割。
