Influence of High Pressure on Protein-Polysaccharide Interactions

摘要

Probe spectrofluorimetry data for bovine serum albumin (BSA) show a reduction in protein surface hydrophobicity in the presence of dextran sulphate (DS), tau -carrageenan ( tau -CAR) or k-carrageenan (k-CAR) (2.5:1 weight ratio) and after high pressure treatment. Size exclusion chromatography studies for BSA in the presence of polysaccharide indicate electrostatic protein-polysaccharide interactions at low ionic strength and neutral pH, which become much stronger at pH 6.5 but disappear in 0.1 M NaCl. These interactions become considerably stronger after pressure treatment (600 MPa) at low ionic strength. It appears that stronger complex(es) formed during pressurization are not simply due tot he induced change in pH during treatment and the strength of complexation is related to the charge density on the polysaccharide (DS > tau -CAR > k-CAR) [1,2]. Complexation of BSA with DS appears to protect the protein against pressure-induced aggregation at low ionic strength.