High-pressure effects on the molecular aggregation and physicochemical properties of myosin in relation to heat gelation.

ABSTRACT

Myosin was extracted from the M. psoas muscle of rabbits, and dissolved in 0.6M KCl buffer (pH6.5). Effects of high-pressure (HP, 100 to 300MPa, 9min, 25°C) treatment on myosin solubility, molecular traits (molecular weight and morphology), flow behavior and strength of heat-induced myosin gels were studied and compared with the untreated controls. Myosin subjected to 200MPa HP treatment had lower solubility than samples treated at other pressures (P<0.05). Molecular dimerization and morphological swelling of myosin was observed using gel-permeation chromatography and atomic-force microscopy. Additionally, the shear-thinning behavior of myosin solutions (10mg/mL) was improved by HP treatment (≥200MPa), and a positive trend in gel-strength enhancement was inferred. It is postulated that significant morphological changes in myosin accounted for changes in its functional properties, by the influence of HP treatment on protein-protein and/or protein-water interactions. There is a relationship between molecular morphology and the coalescing behavior of myosin, since significant changes of both attributes were observed at pressures ≥200MPa.