2 CALCIUM-CALMODULIN-DEPENDENT PROTEIN-KINASES, WHICH ARE HIGHLY CONCENTRATED IN BRAIN, PHOSPHORYLATE PROTEIN-I AT DISTINCT SITES
2 CALCIUM-CALMODULIN-DEPENDENT PROTEIN-KINASES, WHICH ARE HIGHLY CONCENTRATED IN BRAIN, PHOSPHORYLATE PROTEIN-I AT DISTINCT SITES
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DOI：
10.1073/pnas.78.2.1293
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发表时间：
1981-01-01
期刊：
影响因子：
--
通讯作者：
GREENGARD, P
中科院分区：
文献类型：
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作者：
KENNEDY, MB;GREENGARD, P
两个钙刺激的蛋白激酶活性（ATP：蛋白磷酸转移酶，EC 2.7.1.37）磷酸化蛋白I，一个特定的突触蛋白，被确定在大鼠脑匀浆。其中之一是发现在颗粒和胞质组分和磷酸化的蛋白质I的一个区域，是磷酸化的完整的突触体中的钙，但不cAMP。颗粒酶和部分纯化的胞质酶的Ca刺激需要加入钙调蛋白。目前尚不清楚颗粒酶和细胞溶质酶是否相关。第二种钙刺激蛋白I激酶仅存在于胞质溶胶中，并磷酸化蛋白I的一个区域，该区域在完整的突触体中响应于Ca或cAMP而磷酸化。后一种激酶的Ca刺激可能是由钙调蛋白介导的，从低浓度的三氟拉嗪对其的抑制来判断。这两种钙刺激的蛋白I激酶在脑中的浓度比在其他组织中的浓度更高。通过底物特异性和在DEAE-纤维素上的色谱行为，这2种细胞溶质激酶可相互区分，并与肌球蛋白轻链激酶和磷酸化酶B激酶区分。
Two calcium-stimulated protein kinase activities (ATP:protein phosphotransferase, EC 2.7.1.37) that phosphorylate protein I, a specific synaptic protein, were identified in homogenates of rat brain. One of these is found in the particulate and cytosolic fractions and phosphorylates a region of protein I that is phosphorylated in intact synaptosomes in response to Ca but not to cAMP. The stimulation by Ca of the particulate enzyme and of the partially purified cytosolic enzyme requires the addition of calmodulin. It is not yet known whether the particulate and cytosolic enzymes are related. A 2nd calcium-stimulated protein I kinase is found only in the cytosol and phosphorylates a region of protein I that is phosphorylated in intact synaptosomes in response to either Ca or cAMP. The Ca stimulation of this latter kinase is probably mediated by calmodulin, judging from its inhibition by low concentrations of trifluoperazine. Both of the Ca-stimulated protein I kinases are more highly concentrated in brain than in other tissues. The 2 cytosolic kinases are distinguishable from each other and from myosin light chain kinase and phosphorylase b kinase by their substrate specificities and their chromatographic behavior on DEAE-cellulose.