Marie J, Buc H, Simon M P, Kahn A
Eur J Biochem. 1980;108(1):251-60. doi: 10.1111/j.1432-1033.1980.tb04718.x.
Human red cell contain soluble adenosine-3',5'-phosphate-dependent protein kinases, which are able to phosphorylate the L' subunits of erythrocyte pyruvate kinase. Efficiency and maximum level of phosphorylation are very comparable in human liver and red cells. Phosphorylation of red cell pyruvate kinase results in the same kinetic modifications as for liver enzyme, namely a shift towards a 'T' allosteric state characterized by a decreased affinity for phosphoenolpyruvate and increased inhibition by the allosteric inhibitors ATP and alanine. In the course of red cell aging a small amount of partially proteolysed pyruvate kinase, devoid of the phosphorylatable site, appears; it resembles the subtilisin-treated L'4 enzyme and accounts for less than 20% of total pyruvate kinase subunits. Endogenous phosphorylation of pyruvate kinase from erythrocytes incubated in the presence of cyclic nucleotides produces the same kinetic modifications as phosphorylation in partially purified extract; this, however, does not change glucose consumption, lactate production and glycolytic intermediate concentrations of the incubated cells.
人类红细胞含有可溶性腺苷 - 3',5'-磷酸依赖性蛋白激酶，该激酶能够使红细胞丙酮酸激酶的L'亚基磷酸化。在人类肝脏和红细胞中，磷酸化的效率和最大水平非常相似。红细胞丙酮酸激酶的磷酸化导致与肝脏酶相同的动力学修饰，即向“T”变构状态转变，其特征是对磷酸烯醇丙酮酸的亲和力降低，以及变构抑制剂ATP和丙氨酸的抑制作用增强。在红细胞衰老过程中，会出现少量缺乏可磷酸化位点的部分蛋白水解的丙酮酸激酶；它类似于经枯草杆菌蛋白酶处理的L'4酶，占丙酮酸激酶亚基总数的不到20%。在存在环核苷酸的情况下孵育的红细胞中丙酮酸激酶的内源性磷酸化产生与部分纯化提取物中的磷酸化相同的动力学修饰；然而，这不会改变孵育细胞的葡萄糖消耗、乳酸产生和糖酵解中间产物浓度。
