大鼠心脏AMP脱氨酶的调节特性

Regulatory properties of rat heart AMP deaminase.

作者信息

Kaletha K, Składanowski A

出版信息

Biochim Biophys Acta. 1979 May 10;568(1):80-90. doi: 10.1016/0005-2744(79)90275-4.

Abstract

The kinetic and regulatory properties of purified rat heart AMP deaminase were investigated. In the presence of 100 mM KCl, the enzyme exhibited a slightly sigmoid-shaped plot of reaction rate, vs. substrate concentration, which shifted to a more hyperbolic form when ATP, ADP or GTP were added. ATP was the most potent activator of the enzyme, whereas GTP at low (less than 0.25 mM) concentrations increased the enzyme activity. The activation effect was negligible at higher concentrations of GTP. The calculated value of K0.5 of approx. 3 mM for unactivated enzyme decrased to approx. 0.6 mM and 1.1 mM when 0.5 mM ATP or 1.5 mM ADP were present in the incubation mixture, respectively. The theoretical model (Monod, J., Wyman, J. and Changeux, J.P. (1965) J. Mol. Biol. 12, 88-118) gave a partial explanation of these results.

摘要

对纯化的大鼠心脏AMP脱氨酶的动力学和调节特性进行了研究。在100 mM KCl存在下，该酶的反应速率与底物浓度的关系呈轻微的S形曲线，当加入ATP、ADP或GTP时，曲线转变为更接近双曲线的形式。ATP是该酶最有效的激活剂，而低浓度（低于0.25 mM）的GTP可增加酶活性。在较高浓度的GTP下，激活作用可忽略不计。未激活酶的K0.5计算值约为3 mM，当孵育混合物中存在0.5 mM ATP或1.5 mM ADP时，分别降至约0.6 mM和1.1 mM。理论模型（莫诺德，J.，怀曼，J.和尚热，J.P.（1965年）《分子生物学杂志》12卷，88 - 118页）对这些结果给出了部分解释。