Ederveen A G, van der Leest J V, van Emst-de Vries S E, de Pont J J
Department of Biochemistry, University of Nijmegen, The Netherlands.
Eur J Biochem. 1989 Nov 6;185(2):461-8. doi: 10.1111/j.1432-1033.1989.tb15137.x.
Subcellular fractionation of rabbit pancreatic acini was performed to study the distribution of endogenous substrates for protein kinase C. Substrates for protein kinase C were found to be predominantly low molecular mass proteins of cytosolic origin. At least three of these soluble substrates, with molecular masses of 17-19 kDa, were relatively heavily phosphorylated by endogenous as well as purified pancreatic protein kinase C. In the same molecular mass range, 16-18 kDa, soluble proteins were also phosphorylated by protein kinase A. Moreover, addition of cyclic AMP under conditions that activated protein kinase C gave a more than additive labelling of these low molecular mass proteins. The latter observation may be of interest in view of the potentiating effect cyclic-AMP-activated protein kinase A has on amylase secretion stimulated by secretagogues which increase free cytosolic Ca2+ and activate protein kinase C.
为了研究蛋白激酶C内源性底物的分布，对兔胰腺腺泡进行了亚细胞分级分离。发现蛋白激酶C的底物主要是胞质来源的低分子量蛋白质。这些可溶性底物中至少有三种，分子量为17 - 19 kDa，被内源性以及纯化的胰腺蛋白激酶C相对大量地磷酸化。在相同分子量范围内，16 - 18 kDa的可溶性蛋白质也被蛋白激酶A磷酸化。此外，在激活蛋白激酶C的条件下添加环磷酸腺苷，对这些低分子量蛋白质产生了超过相加效应的标记。鉴于环磷酸腺苷激活的蛋白激酶A对由增加游离胞质钙离子并激活蛋白激酶C的促分泌剂刺激的淀粉酶分泌具有增强作用，后一观察结果可能是有意义的。
