THALLIUM (I) ACTIVATION OF PYRUVATE KINASE
THALLIUM (I) ACTIVATION OF PYRUVATE KINASE
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DOI：
10.1016/0003-9861(71)90204-9
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发表时间：
1971-01-01
影响因子：
3.9
通讯作者：
KAYNE, FJ
中科院分区：
文献类型：
--
作者：
KAYNE, FJ
已发现铊（I）在兔肌肉丙酮酸激酶的活化中充当所需的单价阳离子（EC 2.7.1.40）。所观察到的最大速度约为K+激活系统的60%，该值类似于Rb+，一种具有近似相同离子半径的阳离子。在2 mmTI+的水平下达到最大激活。亲和力在很小程度上取决于存在的二价活化剂的浓度，表明一些蛋白质介导的作用。在高的T1+浓度下，发生反应的抑制，这显示出最可能是由于T1+-ADP复合物的形成。放射性同位素204 Tl+的研究表明，有四个结合位点，对应于活性位点的数量。
Thallium (I) has been found to serve as the required monovalent cation in the activation of rabbit muscle pyruvate kinase (EC 2.7.1.40). The observed maximum velocity is approximately 60% that of the K+-activated system; a value similar to that for Rb+, a cation with approxiately the same ionic radius.The kinetically determined affinity of Tl+for pyruvate kinase is approximately 50 times that observed for K+. Maximal activation is reached at a level of 2 mmTl+. The affinity depends to a small degree on the concentration of the divalent activator present, indicating some protein-mediated effect. At high Tl+concentrations, an inhibition of the reaction occurs which, is shown to be most likely due to the formation of the T1+-ADP complex. Studies with the radioactive isotope204Tl+indicated that four binding sites were available, corresponding with the number of active sites.