Purification, Characterization, and Radiolabeling of Lingcod (Ophiodon Elongatus) Skin Type I Collagen

The acid-solubilized collagen of lingcod skin has been extracted, purified and characterized. The skin collagen was readily solubilized by 0.5 M acetic acid, pH 2.5, treatment and further purified by fractional salt precipitation. The purified type I collagen had a melting temperature of about 20C, and its content in the skin of lingcod was high, as has the content of type I collagen been reported for land mammalian and avian skin. Analysis of the collagen by sodium dodecylsulfate-polyacrylamide electrophoresis indicated the presence of three different α-chains, α1, α2, and α3, which is the same structural composition of skin type I collagen found in Atlantic cod, Alaska pollack, blue grenadier and several other teleosts examined. The amino acid composition of lingcod skin type I collagen was very similar to the amino acid composition of Atlantic cod skin collagen, but was not strictly homologous with type I collagen from carp, invertebrate aquatic mammals and mammalian muscles. The purified collagen was radiolabeled to high specific radioactivity and used as a substrate for the assay of Pacific rockfish skeletal muscle matrix metalloproteinases. Radiolabeling did not show any apparent effect on the melting temperature or fibril formation properties of collagen. The radiolabelled lingcod type I collagen fibrils form at 15C and can be used to assay collagenolytic activity from fish at this temperature.