Gergely P, Bot G
Acta Biochim Biophys Acad Sci Hung. 1981;16(3-4):163-78.
Phosphorylase kinase from rabbit skeletal muscle inhibited the dephosphorylation of phosphorylase a by phosphoprotein phosphatase. Phosphorylation (activation) of phosphorylase kinase by cyclic AMP-dependent protein kinase greatly increased this inhibitory effect. Thus, phosphoprotein phosphatase is inhibited by phosphorylase kinase in a reversible manner (Gergely et al. (1976) Biochim. Biophys. Acta 429 809-816). In this paper the regulation by phosphorylase kinase at phosphoprotein phosphatase activity in different fractions of muscle extract and in the presence of various ligands has been investigated. The presence of phosphorylase kinase also affected the ligand control of phosphatase activity. Phosphorylase kinase almost cancelled the inhibitory effect of AMP but hardly influenced the activating effect of glucose, glucose 6-phosphate and caffeine. Calmodulin, glycogen and phosphorylase b (effectors of phosphorylase kinase) did not influence the inhibitory effect of phosphorylase kinase. Fractions of muscle extract also demonstrated the regulatory role of phosphorylase kinase. These fractions contained considerable amounts of phosphorylase kinase and phosphatase. Phosphatase activity was inhibited by phosphorylation reactions triggered by Mg++ and ATP. Heat-stable inhibitors were absent from these fractions, therefore the transient inhibition of phosphatase could be attributed to the phosphorylation of endogenous phosphorylase kinase. The introduction between phosphorylase kinase and phosphatase resulted in a loss of AMP sensitivity, i.e. AMP did not inhibit the activity of phosphatase in those fractions. Our results imply that the phosphorylation of phosphorylase kinase is equally important both in the formation of enzymatically active phosphorylase a and in the inhibition of dephosphorylation of phosphorylase a. The consequence of these two effects is the elevated level of phosphorylase a.
兔骨骼肌磷酸化酶激酶可抑制磷酸蛋白磷酸酶对磷酸化酶a的去磷酸化作用。环腺苷酸依赖性蛋白激酶对磷酸化酶激酶的磷酸化（激活）作用极大地增强了这种抑制效果。因此，磷酸蛋白磷酸酶可被磷酸化酶激酶以可逆方式抑制（格热利等人，（1976年）《生物化学与生物物理学学报》429 809 - 816）。本文研究了磷酸化酶激酶在肌肉提取物不同组分中以及在各种配体存在时对磷酸蛋白磷酸酶活性的调节作用。磷酸化酶激酶的存在也影响了磷酸酶活性的配体调控。磷酸化酶激酶几乎消除了AMP的抑制作用，但对葡萄糖、6 - 磷酸葡萄糖和咖啡因的激活作用影响很小。钙调蛋白、糖原和磷酸化酶b（磷酸化酶激酶的效应物）不影响磷酸化酶激酶的抑制作用。肌肉提取物的组分也证明了磷酸化酶激酶的调节作用。这些组分含有大量的磷酸化酶激酶和磷酸酶。磷酸酶活性受到Mg++和ATP引发的磷酸化反应的抑制。这些组分中不存在热稳定抑制剂，因此磷酸酶的短暂抑制可归因于内源性磷酸化酶激酶的磷酸化。磷酸化酶激酶和磷酸酶之间的相互作用导致了AMP敏感性的丧失，即AMP在这些组分中不抑制磷酸酶的活性。我们的结果表明，磷酸化酶激酶的磷酸化在酶活性磷酸化酶a的形成以及磷酸化酶a去磷酸化的抑制中同样重要。这两种作用的结果是磷酸化酶a水平升高。
