Studies on a Putative (Na+, K+)-ATPase Inhibitor in Chronic Renal Failure Patient's Serum

Abstract

In order to identify and purify a putative substance which might inhibit (Na +, K +)-ATPase in vitro assay sytem, serum extracts from normal persons and C.RF.(chronic renal failure) patients were chromatographed and active peaks were compared with each other. Rat kidney membrane was partially purified with a sucrose step density gradient ultracentrifugation and used for (Na +, K+)-ATPase source. Deproteinized serum obtained by acidification and boiling was gel chromatographed on Sephadex G-25 column in order to remove salts and inorganic phosphate in the sample which interfered with the assay system. Two active peaks appeared just prior to the total volume and in the total volume fractions, and the former was further investigated. Collected fractions were concentrated with freeze-dryer and rechromatorgraphed on Sephadex G-75-120. One major active peak at total volume fractions was separated to several active peaks by using cation exchange CM-Sephadex C-25 column. These peaks from normal and C.RF. serum were compared with each other respectively. The eluted patterns were similar to each other except that one peak appeared at three fifths of total elution volume was shown to be more active in C.RF. serum than that in normal serum.