ATPase activities and autolysis of kuruma prawn Penaeus japonicus muscle proteins

Abstract

Ca2+-, Mg2+-, Mg2+,Ca2+- and Mg2+-EGTA-ATPase activities of natural actomyosin (NAM) from kuruma prawn (Penaeus japonicus) at different temperatures were determined. The maximal activities of all ATPase were observed at 35 °C and subsequently decreased with increasing temperatures. The loss in Ca2+-sensitivity was noticeable as the temperatures increased, suggesting the denaturation of regulatory proteins. The autolysis of kuruma prawn muscle was also investigated at different temperatures. The maximal autolytic activity was found at 60 °C. NaCl at higher concentrations exhibited the greater inhibitory effect toward autolysis. Metalloproteinase inhibitors including 1,10-phenanthroline, EDTA, EGTA and pyrophosphate at the range of 1-10 mM could inhibit the autolysis of kuruma prawn muscle as evidenced by the lower trichloroacetic acid-soluble peptide content and more myosin heavy chain (MHC) band intensity retained. The result suggested that heat-activated metalloproteinases involved in the autolysis of kuruma prawn muscle at the elevated temperatures.