García-Paramio P, Carmena M J, Román F, Colás B, Prieto J C
Departamento de Bioquímica y Biología Molecular, Universidad de Alcalá, Alcalá de Henares, Spain.
Biosci Rep. 1993 Dec;13(6):313-23. doi: 10.1007/BF01150476.
The properties of protein kinase C (PKC) activity have been studied in cytosolic and membrane fractions from rat and human prostate. Ion exchange chromatography indicated the existence of different PKC isoforms, PKC from rat ventral prostate behaved as a classical Ca(2+)- and phospholipid-dependent enzyme and was activated by 1,2-diacylglycerol as well as by high concentrations of arachidonic acid. PKC activity in the cytosolic fraction was higher and presented different cofactor requirements than that in the membrane fraction. PKC from human benign hyperplastic prostate was also phospholipid dependent, activated by tumor-promotong phorbol esters, and appeared to belong to the group of PKC isozymes which lack Ca2+ sensitivity. Human prostatic PKC activity appeared to be of similar nature in both membrane and cytosolic fractions but the specific activity was higher in the particulate preparation which could be related to the stage of endogenous activation of the enzyme. These results extend previous observations in rat ventral prostate and present evidences on the human counterpart. Forthcoming experiments are needed to establish the exact nature of PKC isozymes and their physiological and pathophysiological role in this gland.
已对来自大鼠和人类前列腺的胞质和膜组分中的蛋白激酶C（PKC）活性特性进行了研究。离子交换色谱法表明存在不同的PKC同工型，大鼠腹侧前列腺中的PKC表现为典型的钙和磷脂依赖性酶，可被1,2 - 二酰基甘油以及高浓度的花生四烯酸激活。胞质组分中的PKC活性较高，与膜组分中的PKC活性相比呈现出不同的辅因子需求。来自人类良性增生前列腺的PKC也是磷脂依赖性的，可被促肿瘤的佛波酯激活，并且似乎属于缺乏Ca2 +敏感性的PKC同工酶组。人类前列腺PKC活性在膜和胞质组分中似乎具有相似的性质，但在颗粒制剂中的比活性较高，这可能与该酶的内源性激活阶段有关。这些结果扩展了先前在大鼠腹侧前列腺中的观察结果，并提供了关于人类对应物的证据。需要进行进一步的实验来确定PKC同工酶的确切性质及其在该腺体中的生理和病理生理作用。
