COSOLVENT-INDUCED ADSORPTION AND DESORPTION OF SERUM-PROTEINS ON AN AMPHIPHILIC MERCAPTOMETHYLENE PYRIDINE-DERIVATIZED AGAROSE-GEL

We studied the effects of the following cosolvents on the adsorption a nd desorption of serum proteins from an amphiphilic mercaptomethylene pyridine-derivatized agarose gel: glucose, sucrose, polyethylene glyco l (PEG), 2-methyl-2,4-pentanediol (MPD), sorbitol, pentaerythritol, gl ycerol, and Na2SO4. The water-structuring salt 0.4 M Na2SO4 was the mo st potent promoter of protein adsorption, followed by 5 M sorbitol and , to a lesser extent, 0.2 M PEG 1000 and 2.25 M MPD. The other cosolve nts (4 M glucose, 1.5 M sucrose, 0.3 M pentaerythritol, and 7.6 M glyc erol) were unable to promote protein adsorption to the gel. Attempts t o modulate the salt-promotion effect of Na2SO4 with different cosolven ts demonstrated the occurrence of synergistic effects for pentaerythri tol, sorbitol, and glucose and antagonistic effects for the other coso lvents. Sorbitol and glycerol were found to be the most interesting co solvents studied, as the first promoted protein adsorption, whereas th e other disrupted protein interaction. As a consequence of these novel findings we propose sorbitol and glycerol, both well-known protein st abilizers, as possible alternatives to water-structuring salts during the adsorption phase and to deleterious organic solvents during the de sorption phase on amphiphilic gels. (C) 1996 Academic Press, Inc.