The effect of antimycotics on secretory acid proteinase of Candida albicans

The effect of antimycotics on secretory aspartate (acid) proteinase, a virulence enzyme of Candida albicans, was investigated. The conditions of the study were such as to induce proteinase production in the stationary phase of growth (25-40 hours), when no antifungal tested, except the polyene derivative methyl partricin, significantly reduced the viability of the culture. Among azole derivatives, fenticonazole (FZ) but not miconazole, fluconazole or ketoconazole, exerted strong inhibition on proteinase, in typical dose-diphasic pattern, (0.01 microgram/ml; 1-10 micrograms/ml). 5-fluorocytosine (5-FC) was also inhibitory at a dose interval 1-10 micrograms/ml. In all cases, the inhibition concerned the synthesis of the enzyme rather that its activity as suggested by the results of comparative ELISA, SDS-PAGE and spectrophotometric methods of proteinase detection. Finally, the inhibition of proteinase production by FZ and 5-FC mainly reflected the effect of these antimycotics on general protein synthesis.