Gergely P, Castle A G, Crawford N
Biochim Biophys Acta. 1980 Mar 14;612(1):50-5. doi: 10.1016/0005-2744(80)90277-6.
Platelet phosphorylase kinase (ATP:phosphorylase phosphotransferase, EC 2.7.1.38) was found to be a Ca2+-sensitive enzyme. It was two Ka values for Ca2+ viz. 0.25 and 2.6 microM, respectively. The "calcium-dependent regulator" or calmodulin can enhance the activity of phosphorylase kinase, increasing its affinity for Ca2+. In the presence of calmodulin phosphorylase kinase has only one, high affinity binding site for Ca2+ (Ka = 0.27 microM). Platelet phosphorylase kinase can be phosphorylated by endogenous cyclic AMP-dependent protein kinase increasing its catalytic activity and this activation process is reversed by dephosphorylation. The changing level of intracellular Ca2+ and cyclic AMP may control the activity of phosphorylase kinase, regulating the mobilization of glycogen.
血小板磷酸化酶激酶（ATP：磷酸化酶磷酸转移酶，EC 2.7.1.38）被发现是一种对Ca2+敏感的酶。它对Ca2+有两个Ka值，分别为0.25和2.6微摩尔。“钙依赖性调节因子”或钙调蛋白可以增强磷酸化酶激酶的活性，增加其对Ca2+的亲和力。在钙调蛋白存在的情况下，磷酸化酶激酶对Ca2+只有一个高亲和力结合位点（Ka = 0.27微摩尔）。血小板磷酸化酶激酶可被内源性环磷酸腺苷依赖性蛋白激酶磷酸化，从而增加其催化活性，而这种激活过程可通过去磷酸化逆转。细胞内Ca2+和环磷酸腺苷水平的变化可能控制磷酸化酶激酶的活性，调节糖原的动员。
