Isolation of an extracellular proteinase (keratinase) from Microsporum canis

Proteolytic activity was demonstrated when a strain of Microsporum canis was cultured in broth with human hair, but not in the medium without hair. The extracellular proteinase (keratinase) was isolated and purified by chromatography. Disc electrophoresis showed one protein band of extracellular proteinase, and the antibody against this enzyme gave a single precipitin line in agar diffusion. The IgG fraction completely neutralized the proteinase activity. The proteinase of M. canis may play a role in infection caused by this fungus, by affecting keratinized tissue such as stratum corneum and hair.