Isolation and characterization of a microbial Arg/Lys carboxypeptidase, carboxypeptidase F

Carboxypeptidase F was isolated from a fungal strain F-33 and characterized. The enzyme has the ability to release arginine and lysine from the carboxy terminus of peptides, and showed high specific activity against arginine (140 units mg-1 protein). Optimal temperature and pH for the enzyme reaction were 55 degrees C and pH 8.5, respectively. The enzyme possessed a high thermal stability. Native molecular weight was estimated to be approximately 450,000. Enzymatic activity was inhibited by Co2+, Cd2+, chelating agents and thiol inhibitors.