Abstract 1. 1. Characterization of collagen isolated from byssus threads produced by the sea mussel, Mytilus edulis, demonstrated several properties identical to bovine hide collagen isolated in the same manner. 2. 2. SDS-polyacrylamide gel patterns and amino acid profiles of byssus thread collagens exhibited a high degree of similarity to bovine hide collagen, and SDS segments of byssus thread collagen and bovine hide collagen exhibited similar band patterns.