Effect of ethanol on the kinetics of rat brain (Na+ + K+) ATPase and K+-dependent phosphatase with different alkali ions.
Effect of ethanol on the kinetics of rat brain (Na+ + K+) ATPase and K+-dependent phosphatase with different alkali ions.
复制标题
乙醇对不同碱离子大鼠脑(Na K ) ATP酶和K依赖性磷酸酶动力学的影响。
DOI：
10.1016/0006-2952(78)90119-3
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发表时间：
1978
影响因子：
5.8
通讯作者：
L. Endrenyi
中科院分区：
文献类型：
--
作者：
H. Kalant;N. Woo;L. Endrenyi
在 120 mM Na+ 和不同浓度的 K+、Rb+、Cs+、Li+ 或 NH4+ 存在下，研究了大鼠脑重微粒体组分中 (Na++ K+) 依赖性 ATP 酶 [(Na + K)-ATPase] 和 K+ 依赖性对硝基苯基磷酸酶 [pNPPase] 的活性。 Scatchard 和 Hill 图表明除 Li+ 之外的所有离子都具有非双曲性（协同性），Li+ 的活性比任何其他测试的离子都要低得多。向孵育混合物中添加 0.22 M 乙醇会产生与 K+、Rb+ 和 Cs+ 的 ATP 酶活性形式竞争性抑制、与 Li+ 的非竞争性抑制以及与 NH4+ 的混合抑制。 pNPPase 活性的变化通常遵循相似但不太明确的模式。两种酶活性的希尔常数值均未改变。这些发现被解释为乙醇通过诱导构象变化来抑制 ATP 酶活性的证据，构象变化改变了离子与各种受体位点结合的结果。
(Na++ K+)-dependent ATPase [(Na + K)-ATPase] and K+-dependentp-nitrophenyl phosphatase [pNPPase] activities in rat brain heavy microsomal fractions were studied in the presence of 120 mM Na+and varied concentrations of K+, Rb+, Cs+, Li+or NH4+. Scatchard and Hill plots indicated non-hyperbolicity (cooperativity) with all except Li+, which supported a considerably lower activity than any of the other ions tested. Addition of 0.22 M ethanol to the incubation mixtures produced a formally competitive inhibition of ATPase activity with K+, Rb+and Cs+, a non-competitive inhibition with Li+, and a mixed inhibition with NH4+. The changes in pNPPase activity generally followed a similar but less clear-cut pattern. The values of the Hill constants were not changed for either enzyme activity. The findings are interpreted as evidence that ethanol inhibits ATPase activity by inducing conformational changes which alter the consequences of ion binding to the various receptor sites.