Detection and characterization of Theileria sergenti proteinases.

The lysate of Theileria sergenti piroplasms was tested for proteinases using sodium dodecyl sulfate-polyacrylamide gel electrophoresis in which substrate was included in gel matrix. Six proteinases of molecular weight 330, 125, 98, 94, 67 and 58 kilodalton (kDa) were detected. From the results of the Triton X-114 phase partition, 330, 125 and 58 kDa proteinases were partitioned into aqueous phase, which indicated that they were not associated with parasite membranes. All these three enzymes were classified into metalloproteinase family because of their sensitivities to metal-ion chelating compounds, ethylenediaminetetraacetic acid (EDTA) and 1,10-phenanthroline. On the other hand, 98 and 94 kDa proteinases were membrane-associated metalloproteinases which were preferentially inhibited by 1,10-phenanthroline. Another metalloproteinase of 67 kDa which was inhibited by EDTA and 1,10-phenanthroline was not associated with parasite membranes. Proteinases of 98 and 94 kDa degraded heat-denatured hemoglobin.