Proteins in Fish Muscle: 18. Sedimentation Patterns of Myosin-B Extracts of Prerigor Cod Muscle

Ultracentrifuge patterns (schlieren optics) of extracts of prerigor cod muscle, obtained by blending with 0.6 M salt solutions, showed only one major component together with a few very minor ones provided the concentration of adenosinetriphosphate (ATP) derived from the muscle was greater than 1.5 × 10−4 M in the extract. At lower ATP concentrations, caused by its enzymic decay in aged extracts or by exhaustion of the muscle either by exercise or electric shock, peaks of heavier components appeared at the expense of the original lighter one. Ultracentrifugation of extracts at the higher ATP level prevented to some extent this change upon aging. Amino acid analyses showed that the sediment from this operation and also the residue from the original extraction had the composition of actin.