Light-induced proteolysis of myosin heavy chain by Rose Bengal-conjugated antibody complexes

The specific light-induced, non-enzymatic digestion of chicken skeletal muscle myosin heavy chain by xanthene dye-conjugated antibodies is reported. The xanthene dye Rose Bengal was conjugated to either a mouse monoclonal anti-myosin primary specific antibody or to goat anti-mouse IgG secondary antibodies. Under our experimental conditions, visible light induced the non-enzymatic breakdown of myosin heavy chains when chicken skeletal muscle myosin either directly formed a complex with Rose Bengal-conjugated anti-myosin antibodies or indirectly formed a complex with anti-myosin antibody-Rose Bengal-conjugated secondary antibodies. The rate of the photochemical reaction depended on irradiation time and temperature. Although SDS–PAGE and immunoblot analyses showed that fragments migrating below the myosin heavy chain polypeptide predominated, these analyses also showed higher molecular mass polypeptides were generated.