Campbell W H, Bernofsky C
Mol Cell Biochem. 1979 May 6;25(1):33-42. doi: 10.1007/BF00211139.
In Saccharomyces cerevisiae, a small proportion of the glucose-6-P dehydrogenase activity is firmly associated with the mitochondrial fraction and is not removed by repeated washing or density-gradient centrifugation. However, the enzyme is released by sonic disruption. Mitochondrial glucose-6-P dehydrogenase that is released by sonication and partially purified has been found to be similar to cytosol glucose-6-P dehydrogenase with respect to electrophoretic mobility, isoelectric point, pH optimum, molecular size, and apparent KM's for NADP+ and glucose-6-P. These results indicate that a single species of glucose-6-P dehydrogenase is synthesized in S. cerevisiae and that the enzyme has more than one intracellular location. Mitochondrial glucose-6-P dehydrogenase may be a source of intramitochondrial NADPH and may function with hexokinase and transhydrogenase to provide a pathway for glucose oxidation that is coupled to the synthesis of mitochondrial ATP. A constant proportion of total glucose-6-P dehydrogenase activity remains compartmented in the mitochondrial fraction throughout the growth cycle.
在酿酒酵母中，一小部分葡萄糖-6-磷酸脱氢酶活性与线粒体部分紧密相关，且不会因反复洗涤或密度梯度离心而去除。然而，该酶可通过超声破碎释放出来。经超声处理释放并部分纯化的线粒体葡萄糖-6-磷酸脱氢酶，在电泳迁移率、等电点、最适pH、分子大小以及对NADP⁺和葡萄糖-6-磷酸的表观米氏常数方面，已被发现与胞质葡萄糖-6-磷酸脱氢酶相似。这些结果表明，酿酒酵母中合成的是单一类型的葡萄糖-6-磷酸脱氢酶，且该酶在细胞内有不止一个定位。线粒体葡萄糖-6-磷酸脱氢酶可能是线粒体内NADPH的一个来源，并可能与己糖激酶和转氢酶共同作用，为葡萄糖氧化提供一条与线粒体ATP合成相偶联的途径。在整个生长周期中，线粒体部分始终保持着总葡萄糖-6-磷酸脱氢酶活性的恒定比例。
