RENATURATION OF METMYOGLOBIN SUBJECTED TO HIGH ISOSTATIC PRESSURE

Metmyoglobin solutions (0.2%) when subjected to pressures of 7.5 to 8. 0 kbars at neutral pH were denatured and on standing only partially re formed the native state. The degree and rate of renaturation, as measu red by resolubilisation, was Very dependent on pH and ionic strength, suggesting that electrostatic forces dominate the protein-protein attr active forces in the aggregate. However, a marked temperature dependen ce indicated that hydrogen bond stabilisation of the aggregate could a lso be significant. Spectral analysis of the solutions and precipitate s suggested that the haem environment in the pressure-denatured state was typical of the ferric pigment of heat-denatured myoglobin. However , the initial colour of suspensions following pressure denaturation ch anged rapidly on standing and may indicate that the initial product of pressure treatment is a very unstable complex that rapidly converts t o the denatured ferric pigment.