Cell-associated and extracellular proteinases in Blastocrithidia culicis: Influence of growth conditions

The proteinase profile of Blastocrithidia culicis was analyzed, as well as how different growth conditions influenced its expression by gelatin-SDS-PA GE and the use of specific proteinase inhibitors. Multiple cell-associated proteinases with molecular masses corresponding to 33, 55, 60 kDa (cysteine proteinases) and 77, 80, 90, and 108 kDa (metalloproteinases) were detecte d using these methods. FLU the metalloproteinases identified were partition ed into the detergent phase after Triton X-114 extract, suggesting that the y are membrane-bound, while all cysteine proteinases were partitioned into the aqueous phase. The proteolytic zymograms were similar when three differ ent media were used for variable times of incubation. However, few quantita tive and qualitative changes were observed. The secreted proteinase profile showed an heterogeneous pattern of enzymatic activities whose expression w as dependent on time of growth and medium composition. However, the extrace llular proteinase activities were abolished by 1,10-phenanthroline, suggest ing that all of them are zinc-metalloproteinases.