Chitinase activity from Candida albicans and its inhibition by allosamidin

Candida albicans chitinase isolated using the Dyno-Mill disruption technique was characterized using an improved radiometric assay procedure. The enzyme had apparent temperature and pH optima of 45 degrees C and 6.5, respectively. The preparation yielded an apparent Km of 3.9 mg chitin ml-1 17.6 mM-N-acetylglucosamine (GlcNAc) equivalents] and V of 2.3 nmol GlcNAc formed min-1 (mg protein)-1. The potential of the streptomycete antibiotic allosamidin as an antifungal agent is discussed in view of its dose-dependent inhibition of C. albicans chitinase activity (IC50 = 0.3 microM). Allosamidin was a potent competitive inhibitor of enzyme activity (Ki = 0.23 microM).