Degradation of collagen types I, III, IV and V by extracellular proteinases of an oral flagellate Trichomonas tenax.

Proteinases secreted by an axenic strain of Trichomonas tenax were active against native types I, III, IV and V collagens when evaluated by polyacrylamide gel electrophoresis. Degradation of all four collagen types was temperature dependent. Basement membrane type IV collagen was digested most effectively. An inhibition of all collagenolytic activities by a specific inhibitor of cysteine proteinases, E-64, and activation by a reducing agent, dithiothreitol, indicated the involvement of cysteine proteinases of the oral flagellate in the cleavage of collagen.