CHARACTERIZATION OF BINDING-SITE OF UREMIC TOXINS ON HUMAN SERUM-ALBUMIN

The interaction of uremic toxins including indole-3-acetic acid (IA), indoxyl sulfate (IS), hippuric acid (HA) and 3-carboxy-4-methyl-5-prop yl-2-furanpropanoic acid (CMPF) with human serum albumin (HSA) has bee n investigated by three methods of fluorescent probe displacement, ult rafiltration and equilibrium dialysis. The binding parameter of CMPF w as found to have the strongest affinity (10(7) M(-1)) among all the ur emic toxins studied. Competitive experiment based on the method of Kra gh-Hansen suggested that IA, IS and HA bind to site II, whereas CMPF b inds to site I. The present limited data indicated that the four uremi c toxins caused inhibition to any endo- or exogenous substances on HSA .