Baumgarten E, Brand M D, Pozzan T
Biochem J. 1983 Nov 15;216(2):359-67. doi: 10.1042/bj2160359.
The activity of pyruvate dehydrogenase in extracts of pig mesenteric lymphocytes was measured under different preincubation conditions. The mitogens concanavalin A and ionophore A23187 both increased pyruvate dehydrogenase activity. In both cases activation required extracellular Ca2+. Digitonin-permeabilized cells required 0.5 microM free Ca2+ for half-maximal activation of pyruvate dehydrogenase. The stimulation by concanavalin A in intact cells was probably not due to changes in effectors of pyruvate dehydrogenase kinase. This evidence suggests that activation of pyruvate dehydrogenase is by Ca2+ activation of pyruvate dehydrogenase phosphatase and supports the view that the cytoplasmic free [Ca2+] rises to something less than 1 microM on stimulation with mitogens.
在不同的预孵育条件下，测定了猪肠系膜淋巴细胞提取物中丙酮酸脱氢酶的活性。促有丝分裂原伴刀豆球蛋白A和离子载体A23187均能提高丙酮酸脱氢酶的活性。在这两种情况下，激活都需要细胞外Ca2+。用洋地黄皂苷通透处理的细胞，丙酮酸脱氢酶半最大激活需要0.5微摩尔游离Ca2+。在完整细胞中，伴刀豆球蛋白A的刺激作用可能不是由于丙酮酸脱氢酶激酶的效应物发生了变化。这一证据表明，丙酮酸脱氢酶的激活是通过丙酮酸脱氢酶磷酸酶的Ca2+激活实现的，支持了在有丝分裂原刺激下细胞质游离[Ca2+]升高至小于1微摩尔的观点。
