ESSNER E, NOVIKOFF A B, MASEK B
J Biophys Biochem Cytol. 1958 Nov 25;4(6):711-6. doi: 10.1083/jcb.4.6.711.
The sites of reaction product resulting from ATPase and 5-nucleotidase activities remaining in parenchymatous cells of osmium-fixed rat liver were studied by electron microscopy of thin sections. These indicate that both ATPase and 5-nucleotidase activities are localized in the plasma membrane where it folds to form the microvilli of the bile canaliculus, and that 5-nucleotidase activity is also present in the microvilli at the sinusoidal aspects of the cells. It is suggested that these enzymes, particularly ATPase, may play a role in molecular transport or in some kind of membrane activity at the cell surface. Of special interest is the apparent differential localization of these enzymes at the absorptive and secretory regions of the plasma membrane of the cell. It may be of interest to study changes in these enzyme localizations in pathologic states, as a sign of changed cell function. Some of the difficulties in the interpretation of enzyme reaction products seen in electron micrographs are discussed.
通过对锇固定大鼠肝脏实质细胞超薄切片的电子显微镜观察，研究了ATP酶和5 -核苷酸酶活性反应产物在这些细胞中的定位。结果表明，ATP酶和5 -核苷酸酶活性均定位于质膜上，此处质膜折叠形成胆小管的微绒毛，且5 -核苷酸酶活性也存在于细胞窦状面的微绒毛中。提示这些酶，尤其是ATP酶，可能在分子转运或细胞表面某种膜活性中发挥作用。特别有趣的是这些酶在细胞质膜吸收和分泌区域的明显差异定位。研究这些酶定位在病理状态下的变化作为细胞功能改变的标志可能是有意义的。文中还讨论了在电子显微照片中解释酶反应产物时遇到的一些困难。
