Cornell N W, Schramm V L, Kerich M J, Emig F A
J Nutr. 1986 Jun;116(6):1101-8. doi: 10.1093/jn/116.6.1101.
To evaluate published indications that about 25% of the gluconeogenic enzyme, phosphoenolpyruvate carboxykinase (PEPCK), is located in mitochondria of adult rat liver, cell fractionations were conducted with hepatocytes isolated from rats that were fed ad libitum or starved for 2 days. Hepatocytes were exposed to digitonin for 10 s, and the released materials were separated from residual cell structures by centrifugation through a layer of brominated hydrocarbon. In addition to PEPCK, activities of 9 other enzymes were measured in the untreated cells and with good recovery in the two fractions obtained with digitonin treatment. By comparison with the release of marker enzymes for the cytosol and mitochondria, the subcellular distribution of PEPCK was determined. With cells from either fed or 2-day-starved rats, this enzyme was released exactly like lactate dehydrogenase and within 2-3% of phosphoglycerate kinase and pyruvate kinase. These results indicate that, even after induction by starvation, at least 97% of PEPCK activity is located in the cytosol of rat liver.
为评估已发表的关于约25%的糖异生酶磷酸烯醇式丙酮酸羧激酶（PEPCK）位于成年大鼠肝脏线粒体中的指征，对自由采食或饥饿2天的大鼠分离出的肝细胞进行了细胞分级分离。将肝细胞用洋地黄皂苷处理10秒，通过一层溴代烃离心将释放的物质与残余细胞结构分离。除了PEPCK，还在未处理的细胞以及用洋地黄皂苷处理获得的两个组分中测定了其他9种酶的活性，且回收率良好。通过与胞质溶胶和线粒体的标志物酶的释放情况进行比较，确定了PEPCK的亚细胞分布。无论是来自自由采食大鼠还是饥饿2天大鼠的细胞，这种酶的释放情况与乳酸脱氢酶完全一样，且在磷酸甘油酸激酶和丙酮酸激酶的2 - 3%范围内。这些结果表明，即使在饥饿诱导后，至少97%的PEPCK活性位于大鼠肝脏的胞质溶胶中。
