Structural stability of fish myosin subfragment-1.

1. Tryptic cleavage of fish myosin subfragment-1 (S-1) revealed its similar substructure of heavy chain to that of rabbit S-1. 2. The structural stability of fish S-1 was studied by thermal denaturation method, and a rapid polymerization of inactivated fish S-1, detected by turbidity increase, was characteristic. 3. The light-chain release and tryptic susceptibility increase upon heating were significant with fish S-1.