Binding of proteins to copolymers of varying hydrophobicity

Hydrophobic interactions between proteins and amphiphilic polyelectrolytes were studied by frontal analysis continuous capillary electrophoresis (Gao et al., Analytical Chemistry, 1997, Vol. 69, pp. 2945-2951). Binding isothe rms were obtained for beta-lactoglobulin and for bovine serum albumin inter acting with a series of alternating copolymers of maleic acid and alkyl-vin yl ethers of varying hydrophobicity. Although binding between proteins and copolymers increases with increasing alkyl chain length, a minimum alkyl ch ain length of 3-4 methylenes is required for significant hydrophobic intera ctions to occur. These copolymers, like other polyamphiphiles, can form int rapolymer micelles, and the extent of such micellization decreases with inc reasing degree of carboxylate ionization. Binding results obtained at diffe rent pHs suggest that competition exists between intrapolymer micelle forma tion and protein-polymer hydrophobic interactions. (C) 1999 John Wiley & So ns, Inc.