Kinetic studies of adenosine kinase from L1210 cells: a model enzyme with a two-site ping-pong mechanism.
Kinetic studies of adenosine kinase from L1210 cells: a model enzyme with a two-site ping-pong mechanism.
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L1210 细胞腺苷激酶的动力学研究：具有双位点乒乓机制的模型酶。
DOI：
10.1021/bi00272a012
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发表时间：
1983
期刊：
影响因子：
2.9
通讯作者：
BennettJr,LL
中科院分区：
文献类型：
--
作者：
Chang,CH;Cha,S;Brockman,RW;BennettJr,LL
首页--期刊主要分类--期刊细介绍--期刊题录与文摘--期刊详细文摘内容摘要：从LI210细胞中提纯的腺苷激酶在高浓度腺苷(ADO)、三磷酸腺苷(ATP)和氯化镁的作用下表现出底物抑制作用。当与三磷酸腺苷和氯化镁孵育时，该酶被磷酸化，在没有三磷酸腺苷和氯化镁的情况下，磷酸化的激酶将磷酸盐转移到腺苷。底物结合、同位素交换和动力学研究表明，该酶以磷酸基酶为中间体，通过两位点乒乓机制催化反应。在-A中。腺苷5‘-磷酸转移酶，EC 2.7.1.20)从多种哺乳动物来源中得到部分纯化(Caputto，1951；Lindberg等人，1967；Schnebli等人，1967；Murray，1968；Lindberg，1969；Divekar&Hakala，1971；Henderson等人，1972；Shimizu等人，1972；Namm&Leader，1973；Schmidt等人，1974；Dejong，1977)，并从啤酒酵母(Leibach等人，1971)、兔肝(Miller等人，1979)、大鼠脑(Yamada等人，1980)、小鼠白血病L1210细胞(Chang等人，1980)和人肝(Yamada等人，1981)中纯化到表面均一；也有报道将人胎盘蛋白的激酶纯化了3600倍(Andres&Fox，1979)。腺苷激酶和腺苷脱氨酶是腺苷及其类似物代谢的关键酶。免疫缺陷疾病中腺苷脱氨酶的缺失(Fox&Kelley，1978)和腺苷脱氨酶有效抑制剂的发现(Schaeffer&Schwender，1974；Woo等人，1974)导致了人们对腺苷、脱氧腺苷和腺苷类似物的代谢以及负责它们磷酸化的激酶的强烈兴趣(Henderson等人，1980)。Henderson等人(1972)以6-(甲硫基)嘌呤核糖核苷为底物，研究了Ehrlich腹水癌细胞中该酶的动力学行为。认为该酶催化的是以三磷酸腺苷为第一底物，二磷酸腺苷为第一底物的有序双向反应。
Chi-Hsiung Chang,* Sungman Cha, R. Wallace Brockman, and L. Lee Bennett, Jr. abstract: Purified adenosine kinase from LI210 cells displayed substrate inhibition by high concentrations of adenosine (Ado), ATP, and MgCl2. When incubated with ATP and MgCl2, the enzyme was phosphorylated, and the phosphorylated kinase transferred phosphate to adenosine in the absence of ATP and MgCl2. Substrate binding, isotope exchange, and kinetic studies suggested that the enzyme catalyzes the reaction by means of a two-site ping-pong mechanism with thephos-phorylated enzyme as an obligatory intermediate. Among-A. denosine kinase (ATP: adenosine 5'-phosphotransferase, EC 2.7. 1.20) has been partially purified from a variety of mammalian sources(Caputto, 1951; Lindberg et al., 1967; Schnebli et al., 1967; Murray, 1968; Lindberg, 1969; Divekar & Hakala, 1971; Henderson et al., 1972; Shimizu et al., 1972; Namm & Leader, 1973; Schmidt et al., 1974; DeJong, 1977) and purified to apparent homogeneity from brewer’s yeast (Leibach et al., 1971), rabbit liver (Miller et al., 1979), rat brain (Yamada et al., 1980), murine leukemia L1210 cells (Chang et al., 1980), and human liver (Yamada et al., 1981); 3600-fold purification of the kinase of human placenta was also reported (Andres & Fox, 1979). Adenosine kinase and adenosine deaminase are key enzymes in the metabolism of adenosine and its analogues. The absence of adenosine de-aminase in immunodeficiency diseases (Fox & Kelley, 1978) and the discovery of potent inhibitors of adenosine deaminase (Schaeffer & Schwender, 1974; Woo et al., 1974) have re-sulted in intense interest in the metabolism of adenosine, de-oxyadenosine, and adenosine analogues and in the kinases responsible for their phosphorylation (Henderson et al., 1980). The kinetic behavior of the enzyme from Ehrlich ascites tumor cells was studied by Henderson et al.(1972) by using 6-(methylmercapto) purine ribonucleoside as substrate. It was proposed that the enzyme catalyzed an ordered bi-bi reaction with ATP as the first substrate to bind and ADP as the first