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Keratinolytic proteinase produced by Candida albicans
Abstract:
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.
Insights
Candida albicans produces a keratinolytic proteinase (KPase) when grown on human stratum corneum. This enzyme digests stratum corneum proteins, suggesting a role in the fungus's pathogenicity.
Area of Science:
- Microbiology
- Biochemistry
- Medical Mycology
Background:
- Candida albicans is an opportunistic fungal pathogen.
- The ability of C. albicans to degrade host tissues is crucial for its pathogenicity.
- Keratin, a major structural protein in skin and hair, is a potential nutrient source.
Purpose of the Study:
- To investigate the production of keratinolytic proteinase (KPase) by Candida albicans.
- To determine if C. albicans can utilize human skin and hair components as nitrogen sources.
- To characterize the enzyme responsible for keratin degradation.
Main Methods:
- Cultivation of C. albicans in media containing human stratum corneum, human scalp hair, or keratin powder.
- Assay for keratinolytic proteinase (KPase) activity.
- Digestion of alpha-fibrous protein from human stratum corneum.
- Determination of enzyme's pH optimum and inhibition by specific agents (pepstatin A, chymostatin).
Main Results:
- C. albicans produced KPase when grown in a medium containing human stratum corneum.
- No KPase activity against human stratum corneum was observed when grown on hair or keratin powder.
- The enzyme optimally digested alpha-fibrous protein from human stratum corneum at pH 4.0.
- Enzyme activity was inhibited by pepstatin A and chymostatin, indicating it is a carboxyl proteinase.
Conclusions:
- Candida albicans secretes a keratinolytic proteinase (KPase) capable of degrading human stratum corneum.
- The enzyme is a carboxyl proteinase with specific activity against human keratin.
- This KPase likely plays a significant role in the pathogenic mechanisms of C. albicans in vivo.