Stimulating Effect of Fur Seal Muscle Hysrolysate Peptides on Contractile Activity of Actomyosin

This work was undertaken as an introductory step for isolating the biologically active components of the hydrolysate preparation of fur seal skeletal muscle proteins which contain some vasoactive factors as reported previously. This study was carried out with 2 preparations obtained at different fractionation stages, i.e., “unfractionated mixture” and “lyophilized powder”, the latter constituting the second fraction of gel filtration (Sephadex G-25) of the former. The 2 preparations differed in peptide composition, because their relative biuret, ninhydrin and ultraviolet absorption values differed respectively. By paperand thin layer-chromatography, peptide mapping as well as ion exchange column chromatography, both preparations were found to contain more than 22 peptide components, though the lyophilized powder had less than the other. The lyophilized powder showed an accelerating effect on the rates of both superprecipitaion (0.1 ionic strength, pH 7.0) and ATPase activity (0.15 ionic strength, pH 6.4) of fish actomyosins. The acceleration was also positive when Ca and Mg ions were removed by adding GEDTA or EDTA. These effects seem to be involved in the vasoactive and vasodilatory function of the fur seal peptide preparation.