Keratinolytic proteinase produced by Candida albicans

Candida albicans was cultivated in various media that contained human stratum corneum, human scalp hair or keratin powder (cow's hoof) as a nitrogen source. Production of a keratinolytic proteinase (KPase) was observed when C. albicans was incubated in the medium containing stratum corneum. However, there was no production of a KPase that could digest human stratum corneum in the medium containing hair or keratin powder. alpha-fibrous protein extracted from human stratum corneum was digested by the KPase. The pH optimum of the enzyme was 4.0 and enzyme activity was inhibited by pepstatin A and chymostatin. The KPase, a kind of carboxyl proteinase, may be important for C. albicans to enable it to play a pathogenic role in vivo.