The Subfragment Responsible for the Polymerization of Myosin Heavy Chain through SS Bonding during the Heating of Carp Myosin

To decide the subfragment in carp myosin responsible for the polymerization of myosin heavy chain (HC) through SS bonding during the heating at 80°C, carp myosin was digested with α-chymotrypsin into S-1 and rod, and was heated. From the SDS-PAGE patterns (3% polyacrylamide gel) of the heated samples solubilized in 8M urea-2% SDS, two components were found to be produced. The one was observed on the top of the polyacrylamide gel, and the other was just over HC and was 260 kDa in molecular mass. By treating each component with 10% 2-mercaptoethanol, it was found that the former component was made only from S-1 (80 kDa) and the latter was only from rod (130 kDa).Therefore, it was concluded that in the polymerization of HC through SS bonding during the heating of myosin, SH groups on rod is responsible for the formation of HC dimer and those on S-1 is responsible for the HC polymer formation.