Purification and comparison of intracellular proteinase A in Candida spp. isolates from Malaysian and Iranian patients and infected mice

Abstract

To compare the specific intracellular proteinase A activity in clinical isolates of Candida species isolated from Iranian and Malaysian patients, the blood and kidneys of mice infected by Candida cells isolated from these human patients. The intracellular proteinase A was extracted using glass beads and ultracentrifugation from yeasts cells and purified by ion-exchange chromatography (DEAE-cellulose), followed by affinity chromatography (ConA-agarose). Purity of proteinase A was controlled by SDS-PAGE and its identification was realized by western blot. Enzyme activity was performed using azocasein as substrate. Intracellular proteinase A enzyme activity was higher in Candida albicans (C.albicans) than in non-albicans Candida isolates from Malaysian and Iranian patients, mice blood and mice kidneys (P<0.05). In clinical Candida spp. from human patients, proteinase A activity was significantly higher in Malaysian samples than in their Iranian counterparts (P<0.05). However, Candida spp. isolates obtained from blood and kidneys of mice infected by human clinical strains of Candida spp. showed no significant differences in proteinase A activity between Malaysian and Iranian samples (P>0.05). On the other hand, in both clinical and control yeast isolates obtained from Malaysian and Iranian patients, significant differences were found between systemic and non-systemic samples (P<0.05) but this difference was not observed in mice blood and kidneys. In the present study, a strong proteinase A activity was observed for C.albicans and higher expression of this enzyme in clinical isolates from Malaysian and Iranian patients with systemic candidiasis indicated higher virulent nature of this yeast species when compared with non-albicans Candida strains.