脑（钠，钾）-ATP酶：与赤藓红B的双相相互作用。

Brain (Na+,K+)-ATPase: biphasic interaction with erythrosin B.

作者信息

Swann A C

出版信息

Biochem Pharmacol. 1982 Jun 15;31(12):2185-90. doi: 10.1016/0006-2952(82)90512-3.

Abstract

Brain (Na+,K+)-adenosine triphosphatase (EC 3.6.1.3) has both high and low affinity ouabain binding sites. It has been proposed that the high affinity ouabain binding sites characterize a nerve-specific form of the enzyme. Erythrosin B has been reported to inhibit high affinity ouabain binding selectively. The experiments in this paper were carried out in order to characterize the interactions of erythrosin B with (Na+,K+)-ATPase and to examine the specificity of erythrosin B for enzyme with high affinity for ouabain. Inhibition by erythrosin B was biphasic, with a rapid and a slow phase. The rapid phase appeared to be relatively specific for enzyme with high affinity for ouabain, while the slow phase was not. Inhibition by erythrosin B was accelerated by Mg2+ and was retarded by ATP, K+, or Na+ and ATP. Erythrosin B increased apparent affinity of the enzyme for K+ and decreased apparent affinity for Na+ and for ATP. These results indicate that erythrosin B interacts with an ATP site and has effects on cation affinities opposite to those of ATP. Erythrosin B inhibition is proportional to high affinity ouabain binding if brief incubation times and moderate concentrations are used.

摘要

脑（Na⁺，K⁺）-腺苷三磷酸酶（EC 3.6.1.3）具有高亲和力和低亲和力的哇巴因结合位点。有人提出，高亲和力哇巴因结合位点是该酶的一种神经特异性形式的特征。据报道，赤藓红B能选择性抑制高亲和力哇巴因结合。本文进行了实验，以表征赤藓红B与（Na⁺，K⁺）-ATP酶的相互作用，并研究赤藓红B对与哇巴因具有高亲和力的酶的特异性。赤藓红B的抑制作用呈双相性，有快速相和缓慢相。快速相对与哇巴因具有高亲和力的酶似乎相对特异，而缓慢相则不然。Mg²⁺可加速赤藓红B的抑制作用，而ATP、K⁺或Na⁺与ATP则可使其作用延迟。赤藓红B增加了该酶对K⁺的表观亲和力，降低了对Na⁺和ATP的表观亲和力。这些结果表明，赤藓红B与一个ATP位点相互作用，并且对阳离子亲和力的影响与ATP相反。如果采用短时间孵育和适中浓度，赤藓红B的抑制作用与高亲和力哇巴因结合成正比。