Brouta F, Descamps F, Fett T, Losson B, Gerday C, Mignon B
Department of Parasitology & Parasitic Diseases, Faculty of Veterinary Medicine, University of Liège, Belgium.
Med Mycol. 2001 Jun;39(3):269-75. doi: 10.1080/mmy.39.3.269.275.
A keratinolytic protease secreted by a feline clinical isolate of Microsporum canis cultivated in a broth containing feline keratin as the sole nitrogen source was purified from the culture filtrate by affinity chromatography on bacitracin-agarose and by hydrophobic chromatography on octyl-agarose. The enzyme had an apparent molecular mass of 43.5 kDa and the pI was 7.7. It had a significant activity against keratin azure, elastin-Congo red and denatured type I collagen (azocoll). Using the latter substrate, the optimum pH was around 8 and the apparent optimum temperature around 50 degrees C. The protease was strongly inhibited by 1,10-phenanthroline, phosphoramidon and EDTA. The first 13 N-terminal amino acid sequence showed a 61% homology with that of the extracellular metalloprotease of Aspergillus fumigatus and with the neutral protease I of A. oryzae, confirming that this 43.5 kDa keratinase is a metalloprotease. This keratinolytic metalloprotease could be a virulence-related factor involved in pathophysiological mechanisms of M. canis dermatophytosis.
一株犬小孢子菌临床分离株在以猫角蛋白作为唯一氮源的肉汤培养基中培养后分泌出一种角蛋白分解蛋白酶，该酶通过杆菌肽 - 琼脂糖亲和层析和辛基 - 琼脂糖疏水层析从培养滤液中纯化得到。该酶的表观分子量为43.5 kDa，等电点为7.7。它对角蛋白天青、弹性蛋白 - 刚果红和变性I型胶原（偶氮胶原）具有显著活性。以后者为底物时，最适pH约为8，表观最适温度约为50℃。该蛋白酶受到1,10 - 菲啰啉、磷酰胺和EDTA的强烈抑制。前13个N端氨基酸序列与烟曲霉细胞外金属蛋白酶以及米曲霉中性蛋白酶I的序列具有61%的同源性，证实这种43.5 kDa的角蛋白酶是一种金属蛋白酶。这种角蛋白分解金属蛋白酶可能是参与犬小孢子菌皮肤癣菌病病理生理机制的毒力相关因子。
