碱性磷酸酶的磷酸化中间体
Phosphorylated intermediate of alkaline phosphatase.
作者信息
Cocivera M, McManaman J, Wilson I B
出版信息
Biochemistry. 1980 Jun 24;19(13):2901-7. doi: 10.1021/bi00554a013.
We have measured the phosphorylation of the subunits of alkaline phosphatase in the steady state with several substrates and at several pH values. Our results vary from 80% phosphorylation of both subunits at pH7 to only 9% at pH 10. There is no evidence of anticooperativity. With the measurement of kcat, we are able to evaluate rate constants in a minimal scheme. The results show that the main rate influencing steps ar chemical dephosphorylation and dissociation of phosphate. The predominates at pH 7.0 but declines in importance as the pH is raised. Our rate constants for dissociation of phosphate are in agreement with recent NMR studies.
我们在稳态下，使用几种底物并在几个pH值下测量了碱性磷酸酶亚基的磷酸化情况。我们的结果显示，两个亚基的磷酸化程度在pH7时为80%，而在pH10时仅为9%。没有反协同性的证据。通过测量kcat，我们能够在一个最简模型中评估速率常数。结果表明，影响速率的主要步骤是化学去磷酸化和磷酸盐解离。化学去磷酸化在pH 7.0时占主导，但随着pH升高其重要性下降。我们得到的磷酸盐解离速率常数与最近的核磁共振研究结果一致。
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