Mechanism of tyrosine hydroxylase activation by phosphorylation.
Mechanism of tyrosine hydroxylase activation by phosphorylation.
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通过磷酸化激活酪氨酸羟化酶的机制。
DOI：
10.1016/0006-291x(82)92049-6
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发表时间：
1982
影响因子：
3.1
通讯作者：
J. Henry
中科院分区：
文献类型：
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作者：
A. Vigny;J. Henry
来自牛肾上腺髓质的天然酪氨酸羟化酶的 cAMP 依赖性磷酸化增加了酶活性，并诱导其最适 pH 值从 5.8 转变为 6.4。这些效果与添加阴离子（如肝素、硫酸葡聚糖或吗啉乙磺酸）时观察到的效果类似。磷酸化的这些影响已根据聚电解质理论进行了解释，正如之前提出的阴离子激活理论（Vigny, A., and Henry, J. P. (1981) J. Neurochem. 36, 483–489）。我们假设酶上存在一个阳离子调节位点，对活性位点施加负控制。磷酸化会共价修饰该调节位点的电荷。通过酶的有限蛋白水解获得的活性片段的最佳pH值为6.4并且不能被阴离子或磷酸化激活，这一观察结果进一步支持了这一解释。
cAMP-dependent phosphorylation of native tyrosine hydroxylase from bovine adrenal medulla increased the enzyme activity and induced a shift of its pH optimum from 5.8 to 6.4. These effects are similar to those observed on adding anions such as heparin, dextran sulfate or morpholino ethane sulfonic acid. These effects of phosphorylation have been interpreted in terms of the polyelectrolyte theory, as proposed previously for activation by anions (Vigny, A., and Henry, J. P. (1981) J. Neurochem. 36, 483–489). We postulated the existence on the enzyme of a cationic regulatory site exerting a negative control on the active site Phosphorylation would modify covalently the charge of this regulatory site. This interpretation is further supported by the observation that the active fragment obtained by limited proteolysis of the enzyme has a pH optimum at 6.4 and cannot be activated by anions or phosphorylation.