Phosphorylation of cardiac troponin inhibitory subunit (troponin I) and tropomyosin-binding subunit (troponin T) by cardiac phospholipid-sensitive Ca2+-dependent protein kinase.
Phosphorylation of cardiac troponin inhibitory subunit (troponin I) and tropomyosin-binding subunit (troponin T) by cardiac phospholipid-sensitive Ca2+-dependent protein kinase.
复制标题
心肌磷脂敏感的 Ca2 依赖性蛋白激酶使心肌肌钙蛋白抑制亚基（肌钙蛋白 I）和原肌球蛋白结合亚基（肌钙蛋白 T）磷酸化。
DOI：
10.1042/bj2090189
复制
发表时间：
1983
期刊：
影响因子：
--
通讯作者：
Kuo,JF
中科院分区：
文献类型：
--
作者：
Katoh,N;Wise,BC;Kuo,JF
心肌磷脂敏感性钙依赖性蛋白激酶磷酸化心肌肌钙蛋白抑制亚基（肌钙蛋白I）和原肌球蛋白结合亚基（肌钙蛋白T），以游离形式或肌钙蛋白-原肌球蛋白复合物形式存在。肌钙蛋白I和肌钙蛋白T的穷尽磷酸化显示，1.7和2摩尔的磷酸盐被纳入/摩尔的亚基分别。环腺苷酸依赖性蛋白激酶，虽然掺入0.8 mol磷酸/mol肌钙蛋白I，但不能磷酸化肌钙蛋白T。肌钙蛋白I的磷酸化（表观Km = 3.4 μ M; Vmax. = 2.6 μ mol/min/mg酶）或肌钙蛋白T（表观Km = 0.3 μ M; Vmax. = 0.5 μ mol/min/mg酶）被各种试剂抑制，如阿霉素、棕榈酰肉毒碱、三氟拉嗪、蜂毒肽和N-（6-氨基己基）-5-氯萘-1-磺酰胺（化合物W-7）。钙拮抗剂（如维拉帕米），毛喉素和哇巴因无效。这些研究结果表明，肌钙蛋白I和肌钙蛋白T是这种钙离子依赖性蛋白激酶的有效底物，表明其在肌钙蛋白调节的肌原纤维收缩活性中的潜在调节作用。
Cardiac phospholipid-sensitive Ca2+-dependent protein kinase phosphorylated cardiac troponin inhibitory subunit (troponin I) and tropomyosin-binding subunit (troponin T), present either as the free form or as the troponin-tropomyosin complex. Exhaustive phosphorylation of troponin I and of troponin T revealed that 1.7 and 2 mol of phosphate was incorporated/mol of the subunits respectively. Cyclic AMP-dependent protein kinase, though incorporating 0.8 mol of phosphate/mol of troponin I, was unable to phosphorylate troponin T. Phosphorylation of troponin I (apparent Km = 3.4 microM; Vmax. = 2.6 mumol/min per mg of enzyme) or troponin T (apparent Km = 0.3 microM; Vmax. = 0.5 mumol/min per mg of enzyme) by the Ca2+-dependent enzyme was inhibited by various agents, such as adriamycin, palmitoylcarnitine, trifluoperazine, melittin and N-(6-aminohexyl)-5-chloronaphthalene-1-sulphonamide (compound W-7). Ca2+ antagonists (such as verapamil), forskolin and ouabain were ineffective. These findings indicate that troponin I and troponin T were effective substrates for this species of Ca2+-dependent protein kinase, suggesting its potential regulatory role in the contractile activity of myofibrils modulated by troponin.