Evidence for two structurally different forms of skeletal muscle Ca2+-activated protease.

Recent studies on calcium-activated protease (CAF) have indicated that there are two forms of this enzyme, one requiring millimolar levels of Ca2+ and one requiring micromolar levels of Ca2+ for maximal activation. We have attempted to elucidate the biochemical nature of the difference between the two forms by the use of one dimensional peptide maps and immunoautoradiography, and have found that the 80,000-dalton subunits from the two forms differ substantially while the 30,000-dalton subunit appear to be identical.