Interaction between fish myoglobin and myosin in vitro

Interaction between tuna myoglobin and myosins from tuna and sardine was investigated in a model system at 4 °C for up to 24 h. Both sardine and tuna myosins bound progressively with tuna myoglobin as the storage time increased (P < 0.05). The soret absorption peak was noticeable in the myoglobin–myosin mixture. The oxidation of oxymyoglobin in the presence of myosin was generally greater than that found in the absence of myosin (P < 0.05). Oxymyoglobin underwent oxidation to a greater extent in the presence of tuna myosin than sardine myosin (P < 0.05). The interaction between fish myoglobin and myosin also caused changes in reactive sulfhydryl content and altered the tryptophan fluorescent intensity. The loss in Ca2+-ATPase activity of myosin varied with fish species and was governed by the myoglobin added. Thus, the interaction between fish myoglobin and myosin most likely occurred as a function of time and was species-specific.