pH-dependent denaturation of extracellular aspartic proteinases from Candida species

The yeasts Candida albicans. Candida tropicalis, and Candida parapsilosis secrete aspartic proteinases which may enhance virulence. Profiles of pH-dependent irreversible denaturation of such enzymes were determined at 37 degrees C. C. albicans proteinases from both serotypes A and B maintained 50% of their activity near pH 7.25. Proteinases from C. parapsilosis and C. tropicalis lost 50% of their activity at pH 6.75 and pH 6.15, respectively. This suggests that in the infected host only proteinases of C. albicans maintain a native state for any length of time.