Abstract
Calcium-activated neutral proteases (CANPs) were purified from rabbit skeletal muscle and chicken skeletal muscle, and compared as to their electrophoretic properties, metal requirements, subunit amino acid compositions and immunological cross-reactivities. Two kinds of CANPs (μCANP and mCANP) were isolated from rabbit but the chicken tissue lacked one corresponding to μCANP. They were acidic in the order of chicken mCANP, rabbit mCANP, and rabbit μCANP but the difference between the former two was very small. All of them were composed of two subunits, so-called 80K and 30K subunits. The molecular weight of the 30K subunit was the same for these CANPs (28K) but those of the 80K subunit were different (79K for rabbit μCANP, 75K for rabbit mCANP and 81K for chicken mCANP). The calcium-sensitivity of chicken mCANP was very high when compared with that of rabbit mCANP and close to that of rabbit μCANP. Antisera against chicken CANP and those against rabbit CANP cross-reacted with rabbit CANP and chicken CANP, respectively, when examined by immunoelectrotransfer blot techniques.
