Kinetics of interaction between beta-receptors, GTP protein, and the catalytic unit of turkey erythrocyte adenylate cyclase.
Kinetics of interaction between beta-receptors, GTP protein, and the catalytic unit of turkey erythrocyte adenylate cyclase.
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β 受体、GTP 蛋白和火鸡红细胞腺苷酸环化酶催化单元之间相互作用的动力学。
DOI：
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发表时间：
1982
影响因子：
11.1
通讯作者：
A. Levitzki
中科院分区：
文献类型：
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作者：
A. Tolkovsky;S. Braun;A. Levitzki
火鸡红细胞膜腺苷酸环化酶激活的β-激动剂和鸟苷-5 '-基亚氨基二磷酸的动力学探讨作为GTP调节蛋白和催化单位的浓度的函数。结果发现，激活的整体动力学是一阶的，是独立的GTP调节单元N，催化单元C，和激素的浓度在一个非常宽的浓度范围内。已确定限速步骤不涉及GDP从无活性N单元的解离或活化N'和C之间的缔合。此外，发现鸟苷基-5 '-基亚氨二磷酸结合以随机方式发生，并且不是激素依赖性的。这些结果使我们能够排除顺序型的模型，其中N以其非活性形式与受体R结合，在激素激活时以活性形式N'释放，然后与C结合，激活后者。一个可接受的模型，说明所有的数据符合“碰撞耦合”的原始公式，其中N是紧密相关的C在任何时候。
The kinetics of turkey erythrocyte membrane adenylate cyclase activation by beta-agonists and guanyl-5'-yl imidodiphosphate is explored as a function of the concentration of the GTP regulatory protein and of the catalytic unit. It was found that the overall kinetics of activation is first order and is independent of the concentration of the GTP regulatory unit N, the catalytic unit C, and of hormone over a very wide concentration range. It was established that the rate-limiting step does not involve GDP dissociation from the inactive N unit or the association between activated N' and C. Also, it was found that guanyl-5'-yl imidodiphosphate binding occurs in a random fashion and is not hormone dependent. These results enable us to exclude models of the sequential type in which N in its inactive form is bound to receptor R, is released in an active form N' upon hormone activation, and then binds to C, activating the latter. An acceptable model that accounts for all of the data conforms to the original formulation of "collision coupling" in which N is tightly associated to C at all times.