THE INFLUENCE OF CA2-ATPASE ON THE SPEED AND PATTERN OF RIGOR-MORTIS IN FISH SPECIES OR CULTURED AND WILD FISH( CONCENTRATION AROUND MYOFIBRILLAR MG2+)

The influence of Ca2+ concentration around myofibrillar Mg2+-ATPase on the speed and pattern of rigor mortis in fish species or cultured and wild fish was studied. The change of contraction in pillar form muscl e with the lapse of storage time reflected very well the temporal chan ge of gram of tension in muscle of cultured red sea bream, This result showed that the contractile percentage of muscle is very useful on th e progress of rigor mortis. The progress of muscular contraction diffe red among fish species and between cultured and wild fish of the same species, and which were seen in four parameters of rigor mortis: the p rogressive speed, pattern, and the time and level of peak reached. The se four parameters were closely related to one another. The ranking am ong fishes in myofibrillar Mg2+-ATPase activity was not consistent wit h the difference of speed of progression of muscular contraction. The progress of superprecipitation reaction of actomyosin in muscle of cul tured red sea bream was changed remarkably in four parameters by a ver y small difference of Ca2+ concentration, coinciding very well with th e mutual relation among the four parameters on the progress of muscula r contraction. Therefore, it was considered that the difference of the progress of muscular contraction among fish species and between cultu red and wild fish can be mainly caused by the difference of Ca2+-conce ntration around myofibrils.