Protein extraction from chicken myofibrils irrigated with various polyphosphate and NaCl solutions

Physical changes in chicken gastrocnemius myofibrils incubated in 0.1 to 1.0 M NaCl solutions with or without 10 mM ortho-(P), pyro-(PP), tripoly-(TPP) or hexameta- (HMP) phosphate at pH 6.0 were examined by phase-contrast microscopy, electrophoresis, and solubility. PP and TPP performed similarly in promoting protein extraction, P had no apparent effect, and HMP exhibited an intermediate effect. PP, TPP, and HMP treatments markedly improved protein solubility in 0.3 and 0.4 M NaCl through the release of myosin, but the phosphate effect diminished in ≥ 0.6 M NaCl. Overall, phosphates influenced the ultrastructure of myofibrils and extraction of their constituents in the order: PP ≃ TPP > HMP > P ≃ nonphosphate control.