Type 1, 2A, and 2B myosin heavy chain electrophoretic analysis of rat muscle fibers.

Mammalian skeletal muscles are mixture of three type of fibers: type 1, type 2A, and type 2B fibers. Immunological studies and proteolytic analysis of myosin heavy chains from the three type of fibers have demonstrated the presence of distinct myosin isoforms. By using typed single muscle fibers and improving an electrophoretic method we are able to resolve three distinct polypeptides which are demonstrate to correspond to type 1, 2A and 2B myosin heavy chain isoforms by using specific monoclonal antibodies. The analysis of single muscle fibers shows that different myosin heavy chain isoforms are frequently coexpressed in the same muscle fiber.