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Keratinase of Doratomyces microsporus


 The fungus Doratomyces microsporus produced an extracellular keratinase during submerged aerobic cultivation in a medium containing a protein inducer for enzyme synthesis. The keratinase was purified to homogeneity using hydrophobic interaction chromatography followed by gel chromatography. The molecular weight was estimated to be 33 kDa (from SDS-PAGE analysis) or 30 kDa (by gel chromatography), suggesting a monomeric structure. The isoelectric point of the enzyme was determined to be around 9. The optimal pH and temperature for keratinolytic activity were pH 8–9 and 50 °C, respectively. The serine protease inhibitor PMSF totally inhibited the keratinase. The enzyme was not glycosylated. It was capable of hydrolysing different keratinous materials as well as some non-keratinous proteins. Hydrolysis of some synthetic substrates, specific for known proteinases, suggested that the keratinase of D. microsporus is close to proteinase K.

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Received: 9 July 1999 / Received revision: 13 September 1999 / Accepted: 17 September 1999

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Gradišar, H., Kern, S. & Friedrich, J. Keratinase of Doratomyces microsporus . Appl Microbiol Biotechnol 53, 196–200 (2000).

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  • Enzyme
  • Hydrophobic Interaction
  • Serine Protease
  • PMSF
  • Isoelectric Point