THERMODYNAMIC INCOMPATIBILITY OF PROTEINS AND POLYSACCHARIDES IN SOLUTIONS

The thermodynamic incompatibility of proteins and polysaccharides is o f a general nature This phenomenon is observed under conditions which inhibit complexing between proteins and polysaccharides and promote as sociation between macromolecules of the same type, i.e. provide self-a ssociation of biopolymers. Conditions for incompatibility are dependen t on the structure and composition of a given biopolymer pair Incompat ibility decreases in the ol der. carboxyl-containing polysaccharides > neutral polysaccharides > sulphate-containing polysaccharides. Normal ly, linear polysaccharides are more incompatible with proteins than br anched polysaccharides. The difference in hydrophilicity between prote ins and polysaccharides, the so-called AX-effect, is of great importan ce for phase equilibria in protein-polysaccharide-water systems and si gnificantly affects this phenomenon. This is reflected in the marked t ie slope asymmetry of the phase diagrams of mixed protein-polysacchari de solutions.