Autolysis of calcium-activated neutral protease of chicken skeletal muscle.

The conditions and process of autolysis of calcium-activated neutral protease (CANP) were examined. Optimal conditions for autolysis were the same as those required for expression of activity of CANP. The autolysis proceeded rapidly by a strictly limited proteolysis. During autolysis the molecular weight of CANP changed from 82 K (native CANP or mCANP) to 79 K and then 60 K. The 79 K and 60 K molecular species were both active at microM order of Ca2+ (muCANP), whereas the native CANP is active at mM order of Ca2+ (mCANP). Various proteases examined did not produce muCANP from mcanp under the conditions tested. Furthermore, muCANP did not yield muCANP from mCANP at lower Ca2+ concentrations where only muCANP was active. Therefore, muCANP is produced from mCANP only by the specific autolysis of mCANP.