Lai J C, Blass J P
Comp Biochem Physiol C Comp Pharmacol Toxicol. 1985;80(2):285-90. doi: 10.1016/0742-8413(85)90057-x.
Rat brain cytosolic and mitochondrial hexokinase activities were undetectable without added divalent cations. Mg2+ activated cytosolic (K0.5 of Mg2+ = 343 +/- 13 microM) and mitochondrial (K0.5 of Mg2+ = 183 +/- 8 microM) hexokinase in a concentration-related manner. The corresponding values for Mn2+ were 702 +/- 99 and 413 +/- 21 microM respectively. Ca2+, however, activated both forms of hexokinase poorly. In the presence of Mg2+, both Mn2+ and Cu2+ were more potent inhibitors of cytosolic hexokinase than mitochondrial hexokinase, whereas the inhibition of Cd2+ and Ca2+ did not show such selectivity. These results demonstrate that brain mitochondrial and cytosolic hexokinases differ significantly in their responses to divalent cations.
在不添加二价阳离子的情况下，大鼠脑细胞溶质和线粒体己糖激酶活性无法检测到。Mg2+以浓度相关的方式激活细胞质（Mg2+的K0.5 = 343 +/- 13 microM）和线粒体（Mg2+的K0.5 = 183 +/- 8 microM）己糖激酶。Mn2+的相应值分别为702 +/- 99和413 +/- 21 microM。然而，Ca2+对两种形式的己糖激酶激活作用较弱。在Mg2+存在的情况下，Mn2+和Cu2+对细胞质己糖激酶的抑制作用比对线粒体己糖激酶更强，而Cd2+和Ca2+的抑制作用则没有这种选择性。这些结果表明，脑线粒体和细胞质己糖激酶对二价阳离子的反应存在显著差异。
