INFLUENCE OF HIGH-PRESSURE ON BOVINE SERUM-ALBUMIN AND ITS COMPLEX WITH DEXTRAN SULFATE

High-pressure processing of bovine serum albumin (BSA) solutions (0.1- 1 wt % protein, pH ?) has shown decreasing protein surface hydrophobic ity with increasing pressure, which is further reduced in the presence of dextran sulfate (DS) (BSA:DS weight ratio of 2:1 and 4:1). The tot al calorimetric enthalpy Delta H for pure BSA is substantially reduced after treatment at 600 MPa, and both the endothermic peak temperature and the value of Delta H for BSA + DS is reduced under the same treat ment conditions. Size exclusion chromatography indicates extensive pre ssure-induced protein unfolding and aggregation during BSA treatment a t 400 MPa. Complexation with polysaccharide at low ionic strength prot ects the globular protein against pressure-induced aggregation. The lo ss of the protective effect of DS on addition of electrolyte (0.1 M Na Cl) is consistent with the predominantly electrostatic character of th e protein-polysaccharide interaction.