Department of Poultry Science and University Biotechnology Program, North Carolina State University, Raleigh, North Carolina 27695-7608.
Appl Environ Microbiol. 1992 Oct;58(10):3271-5. doi: 10.1128/aem.58.10.3271-3275.1992.
A keratinase was isolated from the culture medium of feather-degrading Bacillus licheniformis PWD-1 by use of an assay of the hydrolysis of azokeratin. Membrane ultrafiltration and carboxymethyl cellulose ion-exchange and Sephadex G-75 gel chromatographies were used to purify the enzyme. The specific activity of the purified keratinase relative to that in the original medium was approximately 70-fold. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis and Sephadex G-75 chromatography indicated that the purified keratinase is monomeric and has a molecular mass of 33 kDa. The optimum pH and the pI were determined to be 7.5 and 7.25, respectively. Under standard assay conditions, the apparent temperature optimum was 50 degrees C. The enzyme is stable when stored at -20 degrees C. The purified keratinase hydrolyzes a broad range of substrates and displays higher proteolytic activity than most proteases. In practical applications, keratinase is a useful enzyme for promoting the hydrolysis of feather keratin and improving the digestibility of feather meal.
从羽毛降解芽孢杆菌 PWD-1 的培养基中分离到一种角蛋白酶，该酶通过水解偶氮角蛋白进行测定。采用膜超滤、羧甲基纤维素离子交换和 Sephadex G-75 凝胶层析对酶进行纯化。与原始培养基相比，纯化角蛋白酶的比活约提高了 70 倍。SDS-聚丙烯酰胺凝胶电泳分析和 Sephadex G-75 层析表明，纯化的角蛋白酶是单体，分子量为 33 kDa。最佳 pH 值和等电点分别为 7.5 和 7.25。在标准测定条件下，表观最适温度为 50°C。该酶在-20°C 下储存稳定。纯化的角蛋白酶水解多种底物，具有比大多数蛋白酶更高的蛋白水解活性。在实际应用中，角蛋白酶是一种促进羽毛角蛋白水解和提高羽毛粉消化率的有用酶。
