Singh D, Loven D P, Stevens R H
Chem Biol Interact. 1982 Jun;40(2):169-75. doi: 10.1016/0009-2797(82)90099-0.
The adenosine 3',5'-cyclic monophosphate (cAMP)-dependent and cAMP-independent kinase activities were measured in the 1,2-dimethylhydrazine (DMH) induced rat colon cancer and in untreated colon. Previous studies had shown that intestinal tumors induced by chronic exposure to DMH contained 2-fold less intracellular cAMP. The present findings indicate that reduction in cAMP-dependent protein kinase activities also occur in colon cancer cells. Similar hydrogen ion dependence (pH 6-7) and approximate association constants (Ka approximately 0.1 microM) were observed for the enzymes existing in both normal and tumor tissues, while the cAMP-dependent tumor protein kinase was found to phosphorylate phosvitin and casein to a greater degree. These recent findings are consistent with the concept that the concentrations of cAMP and activities of its associated enzyme system are inversely related to the cell proliferation state.
在1,2 - 二甲基肼（DMH）诱导的大鼠结肠癌组织和未处理的结肠组织中，检测了环磷酸腺苷（cAMP）依赖性和非cAMP依赖性激酶活性。先前的研究表明，长期接触DMH诱导的肠道肿瘤细胞内cAMP含量减少了一半。目前的研究结果表明，cAMP依赖性蛋白激酶活性在结肠癌细胞中也会降低。正常组织和肿瘤组织中的酶具有相似的氢离子依赖性（pH 6 - 7）和近似的缔合常数（Ka约为0.1 microM），而cAMP依赖性肿瘤蛋白激酶对卵黄高磷蛋白和酪蛋白的磷酸化程度更高。这些最新发现与cAMP浓度及其相关酶系统活性与细胞增殖状态呈负相关的概念一致。
