A non ouabain-like inhibitor of the sodium pump in uremic plasma ultrafiltrates and urine from healthy subjects

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• 作者：Gallice ; Philippe M. ; Kovacic ; Hervé ; N. ; Brunet ; Philippe J. ; Berland ; Yvon F. ; Crevat ; Aimé ; D.
• 关键词：Sodium pump inhibitor ; Uremia ; Ouabain
• 刊名：Clinica Chimica Acta
• 出版年：1998
• 期刊代码：54_00098981
• 类别：med
• 出版时间：May 25, 1998
• 卷：273
• 期：2
• 页码：149-160
• 文件大小：193 K

摘要

A non ouabain-like inhibitor of the sodium pump was separated from uremic plasma ultrafiltrates and normal urine. Under the same chromatographic conditions (C₁₈ column and a gradient of acetonitrile as eluant), ouabain was eluted in a fraction different from the inhibitor. Affinity chromatography based on the formation of a complex between Na,K-ATPase and the inhibitor achieved the differentiation ouabain. Without magnesium and sodium phosphate, ouabain could not bind to enzyme whereas the inhibitor did. A study of Na,K-ATPase enzyme kinetics showed the inhibitor was not competitive for K⁺, which further differentiates it from ouabain. It was uncompetitive for ATP and seemed competitive for Na⁺. These results indicate that the inhibitor acts inside the cell, unlike ouabain, and thus its action mechanism appears to be original.