Jaquet K, Heilmeyer L M
J Muscle Res Cell Motil. 1984 Dec;5(6):677-86. doi: 10.1007/BF00713926.
Phosphorylation of the isolated rabbit skeletal muscle holotroponin complex at troponin-T by phosphorylase kinase is unusual in that it shows maxima and minima. These oscillations are due to protein phosphatase activity present in the preparations. Following tryptic digestion two phosphorylated peptides, I and II, can be isolated. Their amino-acid compositions are identical and correspond to that of the tryptic peptide which contains the two known phosphorylatable sites 149/150 and 156/7 of troponin-T. Peptide I is phosphorylated on both sites and peptide II only on one site. During phosphorylation the doubly phosphorylated peptide I appears first; after a short lag phase peptide II is formed containing only one phosphate. These phenomena probably cause the observed oscillations in the degree of the holotroponin phosphorylation.
磷酸化酶激酶对分离出的兔骨骼肌肌钙蛋白全复合物中肌钙蛋白 - T 的磷酸化情况不同寻常，呈现出最大值和最小值。这些波动是由于制剂中存在的蛋白磷酸酶活性所致。经胰蛋白酶消化后，可分离出两种磷酸化肽段，I 和 II。它们的氨基酸组成相同，与包含肌钙蛋白 - T 两个已知可磷酸化位点 149/150 和 156/7 的胰蛋白酶肽段的氨基酸组成相符。肽段 I 在两个位点都被磷酸化，而肽段 II 仅在一个位点被磷酸化。在磷酸化过程中，首先出现双磷酸化的肽段 I；经过短暂的延迟期后，形成仅含一个磷酸基团的肽段 II。这些现象可能导致观察到的肌钙蛋白全复合物磷酸化程度的波动。
