Lin C W, Sasaki M, Orcutt M L, Miyayama H, Singer R M
J Histochem Cytochem. 1976 May;24(5):659-67. doi: 10.1177/24.5.58927.
The localization of alkaline phosphatase in HeLa cells was examined by electron microscopic histochemistry and subcellular fractionation techniques. Two monophenotypic sublines of HeLa cells which respectively produced Regan and non-Regan isoenzymes of alkaline phosphatase were used for this study. The electron microscopic histochemical results showed that in both sublines the major location of alkaline phosphatase is in the plasma membrane. The enzyme reaction was occasionally observed in some of the dense body lysosomes. This result was supported by data obtained from a subcellular fractionation study which showed that the microsomal fraction rich in plasma membrane fragments had the highest activity of alkaline phosphatase. The distribution of this enzyme among the subcellular fractions closely paralleled that of the 5'-nucleotidase, a plasma membrane marker enzyme. Characterization of the alkaline phosphatase present in each subcellular fraction showed identical enzyme properties, which suggests that a single isoenzyme exists among fractions obtained from each cell line. The results, therefore, confirm the reports suggesting that plasma membrane is the major site of alkaline phosphatase localization in HeLa cells. The absence of any enzyme reaction in the perimitochondrial space in these cultured tumor cells also indicates that the mitochondrial localization of the Regan isoenzyme reported in ovarian cancer may not be a common phenomenon in Regan-producing cancer cells.
通过电子显微镜组织化学和亚细胞分级分离技术检测了碱性磷酸酶在HeLa细胞中的定位。本研究使用了分别产生碱性磷酸酶的Regan同工酶和非Regan同工酶的两个HeLa细胞单表型亚系。电子显微镜组织化学结果显示，在两个亚系中，碱性磷酸酶的主要定位在质膜。在一些致密体溶酶体中偶尔观察到酶反应。亚细胞分级分离研究获得的数据支持了这一结果，该研究表明富含质膜片段的微粒体部分具有最高的碱性磷酸酶活性。这种酶在亚细胞部分中的分布与质膜标记酶5'-核苷酸酶的分布密切平行。对每个亚细胞部分中存在的碱性磷酸酶的表征显示出相同的酶特性，这表明从每个细胞系获得的部分中存在单一同工酶。因此，结果证实了表明质膜是HeLa细胞中碱性磷酸酶定位主要部位的报道。在这些培养的肿瘤细胞的线粒体外间隙中没有任何酶反应，这也表明在卵巢癌中报道的Regan同工酶的线粒体定位在产生Regan的癌细胞中可能不是常见现象。
