On the nature of the interaction between some anionic polysaccharides and proteins

Abstract

Abstract The interactions between myoglobin and bovine serum albumin and the anionic polysaccharides, pectate, alginate and carboxymethyl cellulose, have been studied by differential scanning calorimetry (d.s.c), absorption spectrophotometry and Sephadex chromatography. At pH 6.0 the effect of the polysaccharides on the native proteins is merely to perturb the structure, causing spectral changes in myoglobin and decreased thermal stability in both myoglobin and bovine serum albumin. However, following heat denaturation at this pH much stronger interactions are formed giving rise to stable high molecular weight complexes which inhibit protein‐protein aggregation and hence precipitation. The response of these systems to changes in ionic strength and pH suggest that the interactions are primarily electrostatic in nature and increase as the net positive charge on the protein increases.