Sera and urine from patients with severe uremia and healthy subjects were seperated by means of gel permeation chromatography on Sephadex G15 column with N(C 2H 5) 3 H 2CO 3 buffer as eluent. Two middle molecular peaks(A and B) were detected at 206 nm in normal urine, uremic serum and uremic urine, but these two peaks were hardly observed in the profile of normal sera. In contrast, the absorption at 206 nm of fractions A and B from uremic serum and urine were less than that of fractions A and B from normal urine. Fractions A from normal urine, uremic serum and urine were collected and resolved into 8 to 9 subpeaks at 230 nm by anion exchange chromatography. One of these subpeaks, A 3, was detected in uremic serum and normal urine but undetectable in uremic urine. After a gel permeation chromatography with bidistilled water as eluent for desalting, subfraction A 3 was seperated into two parts designated A 3 Ⅰ and A 3 Ⅱ in order. The results of MALDI TOF MS revealed that the two peaks from both samples were identical respectively, fraction A 3 Ⅰ contained three kinds of components with molecular weight 839.69, 1 007.94 and 2 015.16 and fraction A 3 Ⅱ consisted of other three kinds of components with molecular weight 873.69, 1 106.67 and 1 680.28.
Sera from patients with different courses of chronic renal failure and healthy persons were separated by gel permeation chromatography,and the concentration of middle molecular fraction B were calculated.The concentration of fractions B was increasing with the aggravating of renal failure degree,which indicated that the concentration of fraction B was related to patients′ renal failure.Fractions B from uremic urine,uremic sera or normal urine were resolved into 10 to 17 sub-fractions by ion exchange chromatography.Sub-fractions from normal urine and from uremic sera were assayed for their inhibition for the activity of Na,K-ATPase.The results showed that the Na,K-ATPase activities of the samples with B-8 and B-9 were much lower than that of blank.It is indicated that B-8 and B-9 contained some compounds which could inhibit the activity of Na,K-ATPase.
