Proteinases in pathogenetic Acanthamoeba spp.

Abstract

Proteinases one of the important factors that contribute to the pathogenicity of Acanthamoeba but unfortunately they gained a very little attention. Therefore, this study was conducted to detect the proteinase that presence in the pathogenic Acanthamoeba spp. and characterized them based on their molecular weight, activities at different pH levels either with or without OTT (dithiothreitol), and the effects of inhibitors on the activity. Two species of Acanthamoeba were used in this study, Acanthamoeba sp. (HKL isolate) and Acanthamoeba castellanii (IMR isolate). In this study, the gelatin SOSPAGE gels was used to detect the proteinases in the amoebae. On the gels, two bands A and B bands of proteinases were detected in Acanthamoeba castellanii (IMR isolate). The A band has its molecular weight was -116.0 kOa, and was active at pH 7.0, 7.5, and 8.0 in the presence of OTT, and was inactivated at pH 5.5, 6.0, and 6.5 with OTT. The B band with a molecular weight between 66.2 and 116.0 kOa was active at all pH with or without OTT and was detected in both isolate of Acanthamoeba. The A band was not inhibited by any inhibitors used. The B band in Acanthamoeba castellanii (IMR isolate) was inhibited by antipain, elastatinal, pepstatin, and E-64 (L-trans-epoxysuccinyl-L-leucilamido [4-guanidino]-butano) suggesting that are serine, cysteine, and aspartic proteinase group. There were no inhibitory effects on this proteinase band presence in Acanthamoeba sp. (HKL isolate). The results show that the A band only appears in the Acanthamoeba castellanii (IMR isolate) at higher pH with OTT, while the B band was observed in both of Acanthamoeba at all pH used either with or without OTT.