Isolation of a keratinolytic proteinase from Trichophyton mentagrophytes with enzymatic activity at acidic pH.
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.
Tsuboi
R
R
Department of Dermatology, Juntendo University School of Medicine, Tokyo, Japan.
Ko
I
I
Takamori
K
K
Ogawa
H
H
D002413:Cations, Divalent / Q000494:pharmacology; D005110:Extracellular Space / Q000201:enzymology; D006863:Hydrogen-Ion Concentration; D007526:Isoelectric Point; D007633:Keratins / Q000378:metabolism*; D007700:Kinetics; D008970:Molecular Weight; D010447:Peptide Hydrolases / Q000302:isolation & purification*; D011480:Protease Inhibitors / Q000494:pharmacology; D013379:Substrate Specificity; D014008:Tinea Pedis / Q000382:microbiology; D014249:Trichophyton / Q000201:enzymology*
D002413:Cations, Divalent; D011480:Protease Inhibitors; D007633:Keratins; D010447:Peptide Hydrolases