PRESSURE-INDUCED DIMERIZATION OF METMYOGLOBIN

Pressure treatment at 7.5 kbar of solutions of metmyoglobin led, as shown by electrophoresis and chromatographic analysis, to the formation of spectrally similar monomeric and dimeric forms. The dimer was formed in the pH range 6-10, though maximum formation was around the isoelectric point (pH 6.9). At acid pH no dimer or higher oligomers formed. In sodium chloride (0.5 to 2M), at neutral pH lower concentrations of dimer formed than in its absence. The dimer was stabilized by SDS-labile linkages and had a slightly lower thermal denaturation temperature than the monomer. If similar changes occur with other proteins, then food quality may be modified by pressure treatments.