FORMATION OF COMPLEXES BETWEEN PROTEIN PARTICLES AND LONG AMPHIPHILICPOLYMERS - BINDING ISOTHERMS VERSUS SIZE AND SURFACE OF THE PARTICLES

Typical isotherms of protein binding-here three serum albumins-to hydr ophobically modified polyacrylates (HMPA) were obtained by separation of free proteins from bound ones using capillary electrophoresis and t he frontal analysis method. The main qualitative features of this asso ciation were anticooperativity, high sensitivity to the hydrophobicity of HMPAs, no sensitivity to the size of the proteins, and subtle diff erences related to small variations in primary structure. Keeping the structure of the protein surface unmodified, monomers and covalent dim ers of the protein were compared. In terms of molar ratio, isotherms a ppeared to be not markedly dependent on the protein size. On the contr ary, despite their similarity in terms of molecular weight, ternary st ructure, surface, and binding to fatty acids, human and bovine serum a lbumins show marked differences in the composition of complexes. Short -range interactions, at the surface of the particles, dominate the ass ociation with long HMPA.