Multiple proteolytic activities were detected in the cell lysates of each of Trichomonas vaginalis, Tritrichomonas foetus, Trichomitus batrachorum and Pentatrichomonas hominis. Analysis of the enzymes responsible using electrophoretic techniques, however, demonstrated differences between the four species with respect to number, molecular weight and specific activity of the proteinases. Differences were also demonstrated in the proteinases present In a range of isolates of Trichomonas vaginalis,
Subcellular fractionation studies showed that most of the proteolytic activity in T. vaginalis and Tritrichomonas foetus was associated with the particulate fractions and appeared to be located, along with a number of other hydrolases, in lysosome-like organelles. The results suggested that a heterogeneous population of lysosomes was present In Trichomonas vaginalis.
Two proteinases were partially purified from the cell lysates of T. vaginalis by a combination of gel filtration, ion-exchange chromatography and affinity chromatography. Both activities were shown to be due to cysteine proteinases although they differed with respect to molecular weight, pH optima, isoelectric point and sensitivity to inhibitors.
An electrophoretic technique for the detection and separation of proteinases on gels containing co-polymerlsed gelatin (gelatin-PAGE) was used to demonstrate extracellular proteinase in cell cultures of T. vaginalis and Tritrichomonas foetus. A number of other hydrolase activities were also found to be present extracellularly. Low molecular weight extracellular proteinases that were not found in cell lysates were purified from the medium in which T. vaginalis had been grown and were used to raise antiserum. The antiserum was shown to bind both Intra- and extracellular proteinases of T. vaginalis and also intracellular proteinases in Tritrichomonas foetus.
The gelatin-PAGE technique was also used to investigate the proteinases of a number of other species of protozoa, in particular Leishmania species. A number of differences were found not only between the species investigated but also between developmental forms of the same species.