PRESSURE-INDUCED DIMERIZATION OF METMYOGLOBIN

Pressure treatment at 7.5 kbar of solutions of metmyoglobin led, as sh own by electrophoresis and chromatographic analysis, to the formation of spectrally similar monomeric and dimeric forms. The dimer was forme d in the pH range 6-10, though maximum formation was around the isoele ctric 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-labi le linkages and had a slightly lower thermal denaturation temperature than the monomer. If similar changes occur with other proteins, then f ood quality may be modified by pressure treatments.