Comparison of characteristics of actomyosin from white, pink, and red muscle fiber types in cultured carp

The present study compared and examined the characteristics of actomyosin a mong white (W), pink (P), and red (R) muscle fiber types in carp (cultured) . Both the superprecipitation reaction and the Mg2+-ATPase activity of acto myosin became higher with increased Ca2+ concentration (pCa 7.0-pCa 5.0) an d with decreased adenosine triphosphate (ATP) concentration (3.0-0.5 mM) in all three muscle fiber types. A comparison of the three fiber types shows that the superprecipitation reaction of actomysoin was lower in the order o f W < P < R and, in contrast, was higher for Mg2+-ATPase activity in the or der of W > P > R. A significantly positive correlation between both values was found for each of the three muscle fiber types, but these correlations were clearly different among the three muscle fiber types, and the superpre cipitation reaction of actomyosin was lower in the order of W < P < R when Mg2+-ATPase activity was at the same level. In conclusion, the characterist ics of actomyosin were remarkably different among white, pink, and red musc le fiber types.