FIG 5.
Protease activities of feline T. foetus are attributed to serine and cysteine proteases. (A) Representative gelatin zymography of cellular protein lysates (40 μg each) from feline trichomonad isolates. Lanes 1 to 4, T. foetus isolates (A, D, F, and Sti) from four different domestic cats; lane 5, feline P. hominis. (B) The effect of inhibitors on protease activity of cellular protein lysates (40 μg each) from T. foetus (isolate A). Lanes 1 and 2, no inhibitors (vehicle-treated controls; ethanol [EtOH], diluent for pepstatin A and PMSF; dH2O, diluent for E64 and EDTA); lane 3, 5 mM PMSF; lane 4, 300 μM E64; lane 5, 10 μM pepstatin A; lane 6, 5 mM EDTA. (C) Lane 1, 40 μg of cellular protein lysate from T. foetus (isolate A); lane 2, 40 μg of secretory product from the corresponding isolate; lane 3, 275 μg of secretory product from corresponding isolate (arrow a, serine protease activity; arrow b, presumptive location of CP30/CP8; arrow c, cysteine protease activity). Results observed with isolate A are representative of assays performed concurrently with isolates D, F, and Sti.