Sharma R K, McLaughlin C A, Pitot H C
Eur J Biochem. 1976 Jun 1;65(2):577-86. doi: 10.1111/j.1432-1033.1976.tb10375.x.
Smooth and rough endoplasmic reticulum from rat liver and hepatomas exhibited endogenous protein kinase activity independent of adenosine 3':5'-monophosphate. The phosphorylation of smooth membranes by this process was consistently higher than that of rough membranes. When histone was added along with the smooth endoplasmic reticulum, cyclic AMP stimulated protein phosphorylation. Analysis of membrane-phosphorylated proteins by gel electrophoresis showed 5 major phosphorylated bands with estimated molecular weights of 155 000, 62 000, 50 000, 46 000 and 43 000, whereas major bands having estimated molecular weights of 62 000, 50 000 and 43 000 were found in membranes of the smooth endoplasmic reticulum of the Morris hepatoma 5123 C. Since previous studies in this and other laboratories have demonstrated the similarity of the protein components of membranes of the endoplasmic reticulum of normal liver and hepatoma, our findings indicate an inability of the protein kinase of hepatoma intracellular membranes to phosphorylate protein species that are found in membranes of both liver and the neoplasm.
大鼠肝脏和肝癌组织中的滑面内质网和粗面内质网均表现出不依赖于3':5'-环磷酸腺苷的内源性蛋白激酶活性。通过该过程对滑面内质网的磷酸化作用始终高于粗面内质网。当组蛋白与滑面内质网一起添加时，环磷酸腺苷会刺激蛋白磷酸化。通过凝胶电泳对膜磷酸化蛋白进行分析，显示出5条主要的磷酸化条带，估计分子量分别为155000、62000、50000、46000和43000，而在莫里斯肝癌5123C的滑面内质网膜中发现了估计分子量为62000、50000和43000的主要条带。由于此前本实验室及其他实验室的研究已证明正常肝脏和肝癌内质网膜的蛋白质成分具有相似性，我们的研究结果表明，肝癌细胞内膜的蛋白激酶无法磷酸化在肝脏和肿瘤膜中均存在的蛋白质种类。
