钒酸盐对钠钾ATP酶和钾依赖性对硝基苯磷酸酶的抑制作用：动力学分析

Vanadate inhibition of Na+K+. ATPase and K+-dependent p-nitrophenylphosphatase: a kinetic analysis.

作者信息

Blázovics A, Vodnyánszky L, Somogyi J, Horváth I

出版信息

Acta Biochim Biophys Acad Sci Hung. 1983;18(3-4):199-209.

Abstract

Vanadate in redox state +5 inhibited the Na+K+-activated ATPase as well as the potassium-stimulated p-nitrophenylphosphatase (p-NPPase) activities of plasma membrane fragments prepared from rat brain. Vanadate exhibited a mixed type inhibition on the Na+K+-ATP-ase activity. The same type of inhibition was observed when the p-NPPase activity of the enzyme preparation was measured either in the presence of 20 mM K+ or with 5 mM Na+ + 1 mM K+. When the reaction mixture contained 50 microM ATP, 5 mM Na+ and 1 mM K+, inhibition of p-NPP hydrolised by vanadate displayed a noncompetitive character. Higher noradrenalin concentration was required for counteracting, the inhibition of p-NPPase by vanadate in the presence of ATP than in its absence.

摘要

氧化态为 +5 的钒酸盐可抑制从大鼠脑制备的质膜片段的 Na+K+ 激活的 ATP 酶以及钾刺激的对硝基苯磷酸酶（p-NPPase）活性。钒酸盐对 Na+K+-ATP 酶活性表现出混合型抑制作用。当在 20 mM K+ 存在下或 5 mM Na+ + 1 mM K+ 条件下测量酶制剂的 p-NPPase 活性时，观察到相同类型的抑制作用。当反应混合物含有 50 μM ATP、5 mM Na+ 和 1 mM K+ 时，钒酸盐对 p-NPP 水解的抑制表现出非竞争性特征。与不存在 ATP 时相比，在存在 ATP 的情况下，需要更高浓度的去甲肾上腺素来抵消钒酸盐对 p-NPPase 的抑制作用。