Cross-reactivity of a monoclonal antibody to the catalytic subunit of chicken gizzard desmin-specific calpain.

The desmin-specific calpain I from chicken gizzard smooth muscle is a dimer of 83 and 35 kDalton subunits. A monoclonal antibody to the large subunit did not cross-react with chicken gizzard and hamster skeletal muscle calpain II, but it did recognize hamster skeletal muscle desmin-specific calpain I and the denatured calpain II from chicken gizzard smooth muscle. These results indicate that different desmin-specific calpains have similar large subunits which differ significantly from the large subunit of calpain II in the same tissue.