Isolation and characterization of tropomyosin from fish muscle.

A comprehensive survey of tropomyosin from various fish myotomal muscles is reported. The fish tropomyosins were blocked at the N-terminus and, as expected, were found to be of similar amino acid composition, alpha-helical content (> 90% at 10 degrees C) and molecular weight to other vertebrate striated muscle forms. The tropomyosins of salmonids and herring muscle were noticeably heterogeneous when assessed by 2D-PAGE. The distribution of isoforms was tissue-specific: slow muscle contained alpha-type tropomyosin while fast muscle contained beta-type tropomyosin. In other species (cod, haddock, wolf-fish and sharks) alpha-type tropomyosins were present in both kinds of muscle but beta-tropomyosin was absent.