Vandenheede J R, Vanden Abeele C, Merlevede W
FEBS Lett. 1987 Jun 1;216(2):291-4. doi: 10.1016/0014-5793(87)80708-1.
The dephosphorylation of the modulator subunit is an essential step in the kinase FA-mediated activation of the ATP,Mg-dependent protein phosphatase. Mg2+ is implicated in this autocatalytic dephosphorylation which is not effected by the addition of phosphoinhibitor-1. Dephosphorylation of free modulator by the catalytic subunit is also largely Mg2+-dependent but can be abolished by phosphoinhibitor-1 in concentrations comparable to the amount of modulator used as substrate (micromolar). The phosphorylase phosphatase activity of the catalytic subunit is inhibited by nanomolar concentrations of phosphoinhibitor-1 and is completely independent of divalent cations.
调节亚基的去磷酸化是激酶FA介导的ATP、Mg依赖性蛋白磷酸酶激活过程中的一个关键步骤。Mg2+参与了这种自身催化的去磷酸化过程，该过程不受磷酸抑制剂-1添加的影响。催化亚基对游离调节亚基的去磷酸化在很大程度上也依赖于Mg2+，但在与用作底物的调节亚基量相当的浓度（微摩尔）下，磷酸抑制剂-1可将其消除。催化亚基的磷酸化酶磷酸酶活性受到纳摩尔浓度的磷酸抑制剂-1的抑制，并且完全不依赖于二价阳离子。
