Jurgensen S R, Chock P B, Taylor S, Vandenheede J R, Merlevede W
Proc Natl Acad Sci U S A. 1985 Nov;82(22):7565-9. doi: 10.1073/pnas.82.22.7565.
We report potent inhibition of the Mg(II).ATP-dependent protein phosphatase, Fc.M, by the regulatory subunit dimer of type II cAMP-dependent protein kinase, RII2. The protein kinase catalytic subunit has no effect on phosphatase activity and is unable to substitute for kinase FA in the kinase FA- and Mg(II).ATP-mediated phosphatase activation reaction. Phosphatase inhibition was investigated as a function of RII2 concentration. The results suggest that RII2 both inhibits the active phosphatase and inhibits phosphatase activation. The inhibition is shown to be noncompetitive with respect to substrate (phosphorylase a). The potential physiological significance of this inhibition is discussed in terms of phosphorylation/dephosphorylation cascade systems involving this kinase and phosphatase.
我们报道了II型环磷酸腺苷（cAMP）依赖性蛋白激酶的调节亚基二聚体RII2对Mg（II）.ATP依赖性蛋白磷酸酶Fc.M具有强效抑制作用。蛋白激酶催化亚基对磷酸酶活性没有影响，并且在激酶FA和Mg（II）.ATP介导的磷酸酶激活反应中无法替代激酶FA。研究了磷酸酶抑制作用与RII2浓度的关系。结果表明，RII2既能抑制活性磷酸酶，又能抑制磷酸酶的激活。这种抑制作用在底物（磷酸化酶a）方面表现为非竞争性。我们从涉及该激酶和磷酸酶的磷酸化/去磷酸化级联系统的角度讨论了这种抑制作用潜在的生理意义。
