钠钾ATP酶化学计量的改变。
Altered stoichiometry of the Na,K-ATPase.
作者信息
Blostein R, Polvani C
机构信息
Montreal General Hospital Research Institute, Quebec, Canada.
出版信息
Acta Physiol Scand Suppl. 1992;607:105-10.
With inside-out membrane vesicles derived from human red cells and incubated at pH > or = 6.6, an altered sodium pump stoichiometry (1Na+:2K+) associated with altered charge transfer is observed when the cytoplasmic Na+ concentration is reduced to very low levels (0.2 mM). With increased proton concentration (approximately pH 6.0), protons can substitute for Na+ or K+ ions such that the Na,K-ATPase can effect either electroneutral Na+/H+ exchange (K+ absent), H+/K+ exchange (Na+ absent), or H(+)-plus-Na+ cotransport in exchange for K+ (low Na+ concentration). Evidence that the stoichiometries of these exchanges are 3Na+/3H+, 2H+/2K+ and 1H(+)-plus-1Na+/2K+, respectively, is presented.
用人红细胞来源的内翻式膜囊泡在pH≥6.6的条件下孵育，当细胞质Na⁺浓度降至非常低的水平（0.2 mM）时，会观察到与电荷转移改变相关的钠泵化学计量比改变（1Na⁺:2K⁺）。随着质子浓度增加（约pH 6.0），质子可替代Na⁺或K⁺离子，使得钠钾ATP酶能进行电中性的Na⁺/H⁺交换（无K⁺）、H⁺/K⁺交换（无Na⁺）或H⁺加Na⁺共转运以交换K⁺（低Na⁺浓度）。文中给出了这些交换的化学计量比分别为3Na⁺/3H⁺、2H⁺/2K⁺和1H⁺加1Na⁺/2K⁺的证据。
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