Rabinkov A G, Amontov S V
V.A. Engelhardt Institute of Molecular Biology, U.S.S.R. Academy of Sciences, Moscow.
Biochim Biophys Acta. 1990 Feb 9;1037(2):216-20. doi: 10.1016/0167-4838(90)90170-k.
The interaction of rat liver acetyl-CoA carboxylase with a 2',3'-dialdehyde derivative of ATP (oATP) has been studied. The degree of the enzyme inactivation has been found to depend on the oATP concentration and the incubation time. ATP was proved to be the only substrate which protected the inactivation. Acetyl-CoA did not effect inactivation, while HCO3- accelerated the process. Ki values for oATP in the absence and presence of HCO3- were 0.35 +/- 0.04 and 0.5 +/- 0.06 mM, and those of the modification constant (kmod) were 0.11 and 0.26 min-1 respectively. oATP completely inhibited the [14C]ADP in equilibrium ATP exchange and did not effect the [14C]acetyl-CoA in equilibrium malonyl-CoA exchange. Incorporation of approximately 1 equivalent of [3H]oATP per acetyl-CoA carboxylase subunit has been shown. No recovery of the modified enzyme activity has been observed in Tris or beta-mercaptoethanol containing buffers, and treatment with NaB3H4 has not led to 3H incorporation. The modification elimination of the ATP triphosphate chain. The results indicated the affinity modification of acetyl-CoA carboxylase by oATP. It was shown that the reagent apparently interacted selectively with the epsilon-amino group of lysine in the ATP-binding site to form a morpholine-like structure.
已对大鼠肝脏乙酰辅酶A羧化酶与ATP的2',3'-二醛衍生物（oATP）的相互作用进行了研究。发现酶的失活程度取决于oATP浓度和孵育时间。已证明ATP是唯一能保护酶不被失活的底物。乙酰辅酶A对失活没有影响，而HCO3-会加速这一过程。在不存在和存在HCO3-的情况下，oATP的Ki值分别为0.35±0.04和0.5±0.06 mM，修饰常数（kmod）分别为0.11和0.26 min-1。oATP完全抑制了平衡ATP交换中的[14C]ADP，而对平衡丙二酰辅酶A交换中的[14C]乙酰辅酶A没有影响。已显示每个乙酰辅酶A羧化酶亚基掺入了约1当量的[3H]oATP。在含有Tris或β-巯基乙醇的缓冲液中未观察到修饰酶活性的恢复，用NaB3H4处理也未导致3H掺入。修饰消除了ATP的三磷酸链。结果表明oATP对乙酰辅酶A羧化酶进行了亲和修饰。结果表明，该试剂显然与ATP结合位点中赖氨酸的ε-氨基选择性相互作用，形成了类似吗啉的结构。
