Velasco G, Iglesias C F, Domínguez P, Barros F, Gascón S, Lazo P S
Biochem Biophys Res Commun. 1986 Sep 30;139(3):875-82. doi: 10.1016/s0006-291x(86)80259-5.
Protein kinase C activity has been identified in cytosolic and membrane fractions from rat and rabbit small intestine epithelial cells. The cytosolic fraction comprised about the 75% of total activity. Protein kinase C activity was resolved from other protein kinase activities by ion exchange chromatography. Phosphatidylserine or phosphatidylinositol were required for protein kinase C to be active. In addition, the activity was enhanced by the presence of a diacylglycerol. Diolein and dimyristin were the most effective (13-14 fold activation). In the presence of phosphatidylserine and diolein, the Ka for activation by Ca2+ was 10(-7)M. The phorbol ester TPA substituted for diacylglycerol in activating protein kinase C. Brush border and basolateral membranes contained protein kinase C activity, although the specific activity of the basal lateral membranes was four-fold higher than the specific activity of the brush border membranes. The presence of PKC in small intestine epithelial cells might have important implications in the Ca2+ mediated control of ionic transport in this tissue.
已在大鼠和兔小肠上皮细胞的胞质和膜组分中鉴定出蛋白激酶C活性。胞质组分约占总活性的75%。通过离子交换色谱法将蛋白激酶C活性与其他蛋白激酶活性分离。蛋白激酶C激活需要磷脂酰丝氨酸或磷脂酰肌醇。此外，二酰基甘油的存在可增强该活性。二油精和二肉豆蔻精最为有效（激活13 - 14倍）。在磷脂酰丝氨酸和二油精存在的情况下，Ca2+激活的Ka为10(-7)M。佛波酯TPA在激活蛋白激酶C时可替代二酰基甘油。刷状缘和基底外侧膜含有蛋白激酶C活性，尽管基底外侧膜的比活性比刷状缘膜的比活性高四倍。小肠上皮细胞中蛋白激酶C的存在可能对该组织中Ca2+介导的离子转运控制具有重要意义。
