Isolation of a keratinolytic proteinase from Trichophyton mentagrophytes with enzymatic activity at acidic pH.

Abstract

A keratinolytic proteinase with enzyme activity at acidic pH was isolated from culture filtrates of Trichophyton mentagrophytes, a major pathogenic fungus of dermatophytosis. The molecular weight of the proteinase was estimated to be 41,000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and 38,000 by gel filtration. The isoelectric point was determined to be 3.9. The proteinase had a pH optimum of 4.5 for keratin and 5.5 for hemoglobin. This enzyme hydrolyzed the synthetic chymotrypsin substrate Suc-Ala-Ala-Pro-Phe-MCA (Km, 0.59 mM), and its activity was strongly inhibited by chymostatin. Previously reported proteinases from dermatophytes have had enzyme activities in neutral or alkaline pH; however, healthy skin has a weakly acidic pH. Thus, the purified proteinase which has an optimal activity at acidic pH and hydrolyzes skin constituents could be an important virulence factor in dermatophytosis.

• Authors: R Tsuboi, I Ko, K Takamori, H Ogawa
• Journal: Infection and immunity (Infect Immun) Vol. 57 Issue 11 Pg. 3479-83 (Nov 1989) ISSN: 0019-9567 [Print] United States
• PMID: 2478474 (Publication Type: Journal Article)

Chemical References

• Cations, Divalent
• Protease Inhibitors
• Keratins
• Peptide Hydrolases

Topics

• Cations, Divalent (pharmacology)
• Extracellular Space (enzymology)
• Hydrogen-Ion Concentration
• Isoelectric Point
• Keratins (metabolism)
• Kinetics
• Molecular Weight
• Peptide Hydrolases (isolation & purification)
• Protease Inhibitors (pharmacology)
• Substrate Specificity
• Tinea Pedis (microbiology)
• Trichophyton (enzymology)