A New Biologically Active Peptide in Fur Seal Muscle

The presence of a new biologically active peptide which has been named callopeptide by the authors was presumed in the digested muscle of fur seal as follows: Skeletal muscle brei including a small portion of bone or internal organs was digested by protease after eliminated fats and oils. Ethanol was added to the digested muscle, the soluble portion obtained at alcohol concentration of 60 to 80 percent passed through a column of Sephadex G-25 after concentrated under reduced pressure to remove the alcohol, and the effluents were divided into four fractions as in Figs. 1 and 2. It was observed that the second fraction develops an intense color by biuret reaction and shows the presence of 12 unknown peptides and small amounts of free amino acids on the chromatogram of amino acid analysis using an analyzer (Table 4). When the test animal (rabbit, cat, etc.) was affected with an aliquot of the second fraction, a strong capillary vasodilatory effect was observed which was disappeared by the complete hydrolysis of this fraction. The biological actions of the fraction are, however, differed from those of vasoactive peptide for instance, bradykinin as shown in Tables 1 and 2, and it was presumed that the digested fur seal muscle contains a new type of biologically active peptide.