Kabir F, Nelson B D
Department of Biochemistry, Arrhenius Laboratory, University of Stockholm, Sweden.
Arch Biochem Biophys. 1989 Oct;274(1):94-9. doi: 10.1016/0003-9861(89)90419-0.
The synthesis and turnover of hexokinase has been measured in Zajdela hepatoma ascites cells labeled for short periods with [35S]methionine. Digitonin fractionation of the labeled cells into a soluble and a membrane fraction showed that only a small part of the newly labeled hexokinase is transferred to mitochondrial binding sites. The soluble enzyme disappears, however, with a half-life of less than 2 h. Glucose had no effect on the stability of the soluble enzyme in intact cells. Our experiments suggest that Zajdela cell hexokinase is synthesized in excess of binding sites and that the excess enzyme is not stable.
用[35S]甲硫氨酸短期标记Zajdela肝癌腹水细胞后，对己糖激酶的合成与周转进行了测定。用洋地黄皂苷将标记细胞分级分离成可溶性部分和膜部分，结果显示新标记的己糖激酶只有一小部分转移到线粒体结合位点。然而，可溶性酶会消失，其半衰期不到2小时。葡萄糖对完整细胞中可溶性酶的稳定性没有影响。我们的实验表明，Zajdela细胞的己糖激酶合成量超过结合位点，且过量的酶不稳定。
