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Partial characterization of the extracellular keratinase from Microsporum canis

Sabouraudia
|January 1, 1984
PubMed

Insights

Microsporum canis releases peptides from human skin proteins using an extracellular enzyme. This enzyme is likely a serine proteinase, as indicated by its inhibition patterns.

Area of Science:

  • Biochemistry
  • Dermatology
  • Microbiology

Background:

  • Extracellular enzymes play crucial roles in microbial pathogenesis and nutrient acquisition.
  • The human stratum corneum, a protective outer layer, contains fibrous proteins like keratin.

Purpose of the Study:

  • To investigate the substrate specificity and enzymatic properties of the extracellular keratinase from Microsporum canis.
  • To characterize the enzyme's potential as a serine proteinase.

Main Methods:

  • Incubation of alpha-type fibrous protein and human stratum corneum fractions with Microsporum canis extracellular keratinase.
  • Enzyme inhibition assays using phenylmethyl-sulfonylfluoride (PMSF), N-ethylmaleimide (NEM), and ethylene glycol tetra-acetic acid (EGTA).

Main Results:

  • The keratinase released peptides from both alpha-type fibrous protein and the membranous fraction of human stratum corneum.
  • Phenylmethyl-sulfonylfluoride strongly inhibited the enzyme.
  • N-ethylmaleimide and ethylene glycol tetra-acetic acid showed weak inhibition, suggesting a serine proteinase mechanism.

Conclusions:

  • Microsporum canis extracellular keratinase effectively degrades human stratum corneum components.
  • The enzyme's inhibition profile strongly suggests it is a serine proteinase, relevant for understanding fungal-host interactions.

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