Comparison of proteinase, lipase and alpha-glucosidase activities from the clinical isolates of Candida species

Proteinase, lipase and α-glucosidase activity in 81 clinically isolated Candida strains grown in nutrient-restricted media were comparatively measured, and the correlation between inducible enzyme activity and fungal growth was analyzed. Enzyme activity was assayed by colorimetric methods. Extracellular proteinase activity was significantly higher in Candida albicans, followed by C. parapsilosis and C. tropicalis. Extracellular lipase activity was observed in all 6 Candida spp. in the descending order of C. albicans, C. tropicalis and C. parapsilosis. Cell surface α-glucosidase activity was significantly higher in C. tropicalis, C. albicans, and C. parapsilosis, but was not detected in the other three species. A relatively strong correlation was observed between proteinase activity and fungal growth (correlation coefficient: 0.72); a mild correlation was observed between lipase activity and fungal growth (0.55); and a slight correlation was obserbed between α-glucosidase activity and fungal growth (0.32). There was no correlation among the strains in the activity levels of the three enzymes. These results suggest that pathogenic fungi produce larger amounts of inducible hydrolytic enzymes, and that proteinase is most likely to be related to fungal growth in nutrient-restricted conditions.