Tsuboi R, Ko I, Takamori K, Ogawa H
Department of Dermatology, Juntendo University School of Medicine, Tokyo, Japan.
Infect Immun. 1989 Nov;57(11):3479-83. doi: 10.1128/iai.57.11.3479-3483.1989.
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.
从须癣毛癣菌（皮肤癣菌病的主要致病真菌）的培养滤液中分离出一种在酸性pH下具有酶活性的角蛋白分解蛋白酶。通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳估计该蛋白酶的分子量为41,000，通过凝胶过滤估计为38,000。确定其等电点为3.9。该蛋白酶对角蛋白的最适pH为4.5，对血红蛋白的最适pH为5.5。这种酶能水解合成的胰凝乳蛋白酶底物Suc-Ala-Ala-Pro-Phe-MCA（Km，0.59 mM），其活性受到抑肽酶的强烈抑制。先前报道的来自皮肤癣菌的蛋白酶在中性或碱性pH下具有酶活性；然而，健康皮肤的pH呈弱酸性。因此，在酸性pH下具有最佳活性并能水解皮肤成分的纯化蛋白酶可能是皮肤癣菌病中的一个重要毒力因子。
