Further purification and some properties of a gelatin-specific proteinase of human leucocytes.

A latent gelatin-specific proteinase (gelatinase) was isolated from the crude extract of human leukocytes. The enzyme was purified about 180-fold (7040 units/mg) with an overall yield of 23%. The isolated protein migrated as a single band on sodium dodecyl sulfate polyacrylamide-gel electrophoresis. Its mobility was unaffected by reducing agent. The protein band corresponded to approx. 90-94 kDa. Gelatinase activity was strongly inhibited by chelating agents, such as EDTA and 1,10-phenanthroline. This inhibition was reversed by Zn2+ and Co2+; other metal ions were less or not at all effective in reversing the inhibition. Moreover, Co2+ stimulated gelatinase activity. These results indicate that Zn2+ and/or Co2+ are essential for the activity of this gelatinase.