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°C and 6·5, respectively. The preparation yielded an apparent K m 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 μM). Allosamidin was a potent competitive inhibitor of enzyme activity (K i = 0·23 μM).