Xie Fuhong, Chao Yapeng, Yang Xiuqing, Yang Jing, Xue Zhiquan, Luo Yuanming, Qian Shijun
State Key Laboratories of Transducer Technology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China.
Bioresour Technol. 2010 Jan;101(1):344-50. doi: 10.1016/j.biortech.2009.08.026. Epub 2009 Sep 4.
Four extracellular keratinases (designated KI, KII, KIII, and KIV) were produced during submerged aerobic cultivation in a medium containing native human foot skin (NHFS) for enzyme synthesis. The molecular weights, determined by SDS-PAGE, were 25, 50, 34, and 19 kDa, respectively. Gel filtration of the four purified enzymes in native conditions indicated that active keratinase KI is a novel homo-octamer, KII a homo-dimer, and KIII and KIV monomers. All four keratinases exhibited high activities at pH 8.0-10.0 with an optimal pH of 9.0. The optimal temperature for keratinolytic activity of KI, KII, and KIII was approximately 50, and 60 degrees C for KIV. One millimolar of PMSF completely inhibited the keratinolytic activities of the four enzymes. The N-terminal sequences of KI, KII, and KIII showed that they were different from previously described enzymes, whereas KIV shared an identical N-terminal sequence with two other peptidases from Streptomyces.
在含有天然人足皮肤（NHFS）用于酶合成的培养基中进行好氧深层培养时，产生了四种细胞外角蛋白酶（分别命名为KI、KII、KIII和KIV）。通过SDS-PAGE测定，它们的分子量分别为25、50、34和19 kDa。在天然条件下对这四种纯化酶进行凝胶过滤表明，活性角蛋白酶KI是一种新型同八聚体，KII是同二聚体，KIII和KIV是单体。所有四种角蛋白酶在pH 8.0 - 10.0时表现出高活性，最适pH为9.0。KI、KII和KIII的角蛋白分解活性的最适温度约为50℃，KIV为60℃。1 mM的苯甲基磺酰氟（PMSF）完全抑制了这四种酶的角蛋白分解活性。KI、KII和KIII的N端序列表明它们与先前描述的酶不同，而KIV与来自链霉菌的另外两种肽酶具有相同的N端序列。
