EFFECT OF ALKALI-METAL CHLORIDES ON THE DISTRIBUTION OF SERUM-ALBUMININ THE WATER INTERFACIAL ADSORPTION LAYER TOLUENE SYSTEM - 1 - ACCUMULATION OF PROTEIN AT THE INTERFACE AND ITS CONCENTRATION IN THE HYDROCARBON PHASE

The radiometric ''scintillating phase'' method was used to investigate the effect of the chlorides of alkali metals (lithium, sodium, potass ium, and cesium) on the distribution of bovine serum albumin (BSA) bet ween the water phase, the interfacial layer, and toluene in a wide ran ge of protein concentrations (from 5.3 x 10(-10) to 6.3 x 10(-5) M). I t was shown that salts, as a rule, increase the relative content of pr otein in the interfacial layer and decrease it in the hydrocarbon phas e. The effects of the maximal accumulation of protein at the interface and its minimal transfer into the hydrocarbon phase are realized in t he salt concentration range varying from 0.1 to 0.3 M. At higher conce ntrations, the salts already do not affect the relative concentrations of protein in the interfacial layer and in the hydrocarbon phase, alt hough the content of protein in the interfacial layer as compared to t hat in the salt-free system remains higher, whereas it is lower in tol uene. The specific effect of potassium chloride at low BSA concentrati ons was noted; this effect exhibits a considerable increase in the rel ative content of protein in both the interfacial layer and in the hydr ocarbon phase. The accumulation dependence of BSA in the interfacial l ayer and its concentration in the hydrocarbon phase on the nature of t he cation is most pronounced at low initial BSA concentrations. At hig h protein concentrations, the effect of the alkali metal chlorides is virtually the same. Thus, the effect of the salts on the investigated system containing two immiscible liquids (water-toluene) and protein i s similar to that known to exist in liquid-liquid systems containing l ow-molecular-weight surfactants, and consisting in the concentration o f surfactants at the interface.