Elnageh K M, Gaitonde M K
Department of Biochemistry, St. George's Hospital Medical School, London, England.
J Neurochem. 1988 Nov;51(5):1482-9. doi: 10.1111/j.1471-4159.1988.tb01115.x.
A simple and rapid method based on the NADH-linked reduction of a tetrazolium dye was described for the determination of pyruvate dehydrogenase activity in rat brain homogenates. The method (method 3) gave a value of 36.06 +/- 1.24 nmol of pyruvate utilised/min/mg of whole brain protein. This value was higher than that obtained by measurement of the rate of decarboxylation of [1-14C]pyruvate (15.10 +/- 0.88 nmol/min/mg of protein; method 1) and was comparable with the rate of transfer of acetyl groups to an arylamine (39.04 +/- 1.32 nmol/min/mg of protein; method 2). A critique of the values reported by others by different methods was given. The pyruvate dehydrogenase activity in the mitochondria isolated from rat brain was in the "active" (nonphosphorylated) form. A deficiency of thiamine in rats was produced by treatment with pyrithiamine, an antagonist of thiamine. This treatment resulted in abnormal neurological signs, such as ataxia and convulsions. The measurement of the total activity of pyruvate dehydrogenase in the brain by all three methods showed no significant change in the enzymic activity in thiamine-deficient rats after treatment with pyrithiamine. The activities of the enzyme in the brains of pair-fed animals were similar to those in the controls.
描述了一种基于四唑盐染料与NADH相关还原反应的简单快速方法，用于测定大鼠脑匀浆中丙酮酸脱氢酶的活性。该方法（方法3）测得每毫克全脑蛋白每分钟利用丙酮酸的量为36.06±1.24 nmol。该值高于通过测量[1-14C]丙酮酸脱羧速率获得的值（15.10±0.88 nmol/分钟/毫克蛋白；方法1），并且与乙酰基转移至芳胺的速率相当（39.04±1.32 nmol/分钟/毫克蛋白；方法2）。对其他人用不同方法报告的值进行了评论。从大鼠脑分离的线粒体中丙酮酸脱氢酶活性处于“活性”（非磷酸化）形式。用硫胺素拮抗剂吡硫胺素处理大鼠可导致硫胺素缺乏。这种处理导致异常的神经体征，如共济失调和惊厥。用所有三种方法测量硫胺素缺乏大鼠脑中丙酮酸脱氢酶的总活性，结果显示用吡硫胺素处理后酶活性无显著变化。成对喂养动物脑中该酶的活性与对照组相似。
