镁离子、三磷酸腺苷和钾离子对（钠+，钾+）三磷酸腺苷酶的可逆抑制作用。

Reversible inhibition of (Na+, K+) ATPase by Mg2+, adenosine triphosphate, and K+.

作者信息

Fagan J B, Racker E

出版信息

Biochemistry. 1977 Jan 11;16(1):152-8. doi: 10.1021/bi00620a026.

Abstract

Adenosine triphosphate (ATP) hydrolysis catalyzed by the plasma membrane (Na+,K+)ATPase isolated from several sources was inhibited by Mg+, provided that K+ and ATP were also present. Phosphorylation of the adenosine triphosphatase (ATPase) by ATP and by inorganic phosphate was also inhibited, as was p-nitrophenyl phosphatase activity. (Ethylenedinitrilo)tetraacetic acid (EDTA) and catecholamines protected from and reversed the inhibition of ATP hydrolysis by Mg2+, K+ and ATP. EDTA was protected by chelation of Mg2+ but catecholamines acted by some other mechanism. The specificities of various nucleotides as inhibitors (in conjunction with Mg2+ and K+) and as substrates for the (Na+, K+) ATPase were strikingly different. ATP, ADP, beta,gamma-CH2-ATP and alpha,beta-CH2-ADP were active as inhibitors, whereas inosine, cytidine, uridine, and guanosine triphosphates (ITP, CTP, UTP, and GTP) and adenosine monophosphate (AMP) were not. On the other hand, ATP and CTP were substrates and beta,gamma-NH-ATP was a competitive inhibitor of ATP hydrolysis, but not an inhibitor in conjunction with Mg2+ and K+. The Ca2+-ATPase from sarcoplasmic reticulum and F1, the Mg2+-ATPase from the inner mitochondrial membrane, were also inhibited by Mg2+. Catecholamines reversed inhibition of the Ca2+-ATPase, but not that of F1.

摘要

从多个来源分离得到的质膜（Na⁺，K⁺）ATP 酶催化的三磷酸腺苷（ATP）水解受到 Mg⁺的抑制，前提是同时存在 K⁺和 ATP。ATP 和无机磷酸对腺苷三磷酸酶（ATP 酶）的磷酸化作用也受到抑制，对硝基苯磷酸酶活性同样如此。（乙二胺四乙酸）（EDTA）和儿茶酚胺可防止并逆转 Mg²⁺、K⁺和 ATP 对 ATP 水解的抑制作用。EDTA 通过螯合 Mg²⁺起到保护作用，而儿茶酚胺则通过其他机制发挥作用。各种核苷酸作为抑制剂（与 Mg²⁺和 K⁺结合时）以及作为（Na⁺，K⁺）ATP 酶的底物时，其特异性存在显著差异。ATP、ADP、β，γ-CH₂-ATP 和 α，β-CH₂-ADP 作为抑制剂具有活性，而肌苷、胞苷、尿苷和鸟苷三磷酸（ITP、CTP、UTP 和 GTP）以及腺苷一磷酸（AMP）则不然。另一方面，ATP 和 CTP 是底物，β，γ-NH-ATP 是 ATP 水解的竞争性抑制剂，但不是与 Mg²⁺和 K⁺结合时的抑制剂。肌浆网的 Ca²⁺-ATP 酶和线粒体内膜的 F1（Mg²⁺-ATP 酶）也受到 Mg²⁺的抑制。儿茶酚胺可逆转对 Ca²⁺-ATP 酶的抑制作用，但不能逆转对 F1 的抑制作用。