Jope R, Blass J P
Biochem J. 1975 Sep;150(3):397-403. doi: 10.1042/bj1500397.
The total activity of pyruvate dehydrogenase in mitochondria isolated from rat brain and liver was 53.5 and 14.2nmol/min per mg of protein respectively. Pyruvate dehydrogenase in liver mitochondria incubated for 4 min at 37 degrees C with no additions was 30% in the active form and this activity increased with longer incubations until it was completely in the active form after 20 min. Brain mitochondrial pyruvate dehydrogenase activity was initially high and did not increase with addition of Mg2+ plus Ca2+ or partially purified pyruvate dehydrogenase phosphatase or with longer incubations. The proportion of pyruvate dehydrogenase in the active form in both brain and liver mitochondria changed inversely with changes in mitochondrial energy charge, whereas total pyruvate dehydrogenase did not change. The chelators citrate, isocitrate, EDTA, ethanedioxybis(ethylamine)tetra-acetic acid and Ruthenium Red each lowered pyruvate dehydrogenase activity in brain mitochondria, but only citrate and isocitrate did so in liver mitochondria. These chelators did not affect the energy charge of the mitochondria. Mg2+ plus Ca2+ reversed the pyruvate dehydrogenase inactivation in liver, but not brain, mitochondria. The regulation of the activation-inactivation of pyruvate dehydrogenase in mitochondria from rat brain and liver with respect to energy charge is similar and may be at least partially regulated by this parameter, and the effects of chelators differ in the two types of mitochondria.
从大鼠脑和肝中分离出的线粒体中，丙酮酸脱氢酶的总活性分别为每毫克蛋白质53.5和14.2纳摩尔/分钟。在37摄氏度下不添加任何物质孵育4分钟的肝线粒体中的丙酮酸脱氢酶，其活性形式占30%，随着孵育时间延长，该活性增加，直至20分钟后完全处于活性形式。脑线粒体丙酮酸脱氢酶活性最初较高，添加Mg2+加Ca2+、部分纯化的丙酮酸脱氢酶磷酸酶或延长孵育时间均不会使其增加。脑和肝线粒体中处于活性形式的丙酮酸脱氢酶比例与线粒体能量电荷的变化呈反比，而丙酮酸脱氢酶的总量不变。螯合剂柠檬酸盐、异柠檬酸盐、乙二胺四乙酸、乙二醇双（乙胺）四乙酸和钌红均可降低脑线粒体中的丙酮酸脱氢酶活性，但只有柠檬酸盐和异柠檬酸盐能降低肝线粒体中的该活性。这些螯合剂不影响线粒体的能量电荷。Mg2+加Ca2+可逆转肝线粒体而非脑线粒体中丙酮酸脱氢酶的失活。大鼠脑和肝线粒体中丙酮酸脱氢酶激活-失活的能量电荷调节相似，且可能至少部分受该参数调节，螯合剂在两种类型线粒体中的作用不同。
