The collagenase, produced extracellular by Bacillus pumilus Col-J, was purified by ammonium sulfate precipitation followed by two gel filtrations, involving Sephadex G-100 column and Sepharose Fast Flow column. Purified collagenase has a 31.53-fold increase in specific activity of 87.33 U/mg and 7.00% recovery. The collagenase has a relative molecular weight of 58.64 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The optimal temperature for the enzyme reaction was 45 degrees C. More than 50% of the original activity still remained after 5 min of incubation at 70 degrees C or 10 min at 60 degrees C. The maximal enzyme activity of collagenase was obtained at pH7.5, and it was stable over a pH range of 6.5-8.0. The collagenase activity was strongly inhibited by Mn2+, Pb2+, ethylenediamine tetraacetic acid, ethylene glycol tetraacetic acid, and beta-mercaptoethanol. However, Ca2+ and Mg2+ greatly increased its activity. The collagenase from B. pumilus Col-J showed highly specific activity towards the native collagen from calf skin. The K-m and V-max of the enzyme for collagen were 0.79 mg/mL and 129.5 U, respectively.