Bressollier P, Letourneau F, Urdaci M, Verneuil B
Laboratoire de Génie Enzymatique et Biovalorisation (Unité du Laboratoire de Chimie des Substances Naturelles), I.U.T., Département de Génie Biologique, Limoges, France.
Appl Environ Microbiol. 1999 Jun;65(6):2570-6. doi: 10.1128/AEM.65.6.2570-2576.1999.
Streptomyces strain K1-02, which was identified as a strain of Streptomyces albidoflavus, secreted at least six extracellular proteases when it was cultured on feather meal-based medium. The major keratinolytic serine proteinase was purified to homogeneity by a two-step procedure. This enzyme had a molecular weight of 18,000 and was optimally active at pH values ranging from 6 to 9.5 and at temperatures ranging from 40 to 70 degrees C. Its sensitivity to protease inhibitors, its specificity on synthetic substrates, and its remarkably high level of NH2-terminal sequence homology with Streptomyces griseus protease B (SGPB) showed that the new enzyme, designated SAKase, was homologous to SGPB. We tested the activity of SAKase with soluble and fibrous substrates (elastin, keratin, and type I collagen) and found that it was very specific for keratinous substrates compared to SGPB and proteinase K.
链霉菌菌株K1-02被鉴定为黄白链霉菌，当它在以羽毛粉为基础的培养基上培养时，会分泌至少六种细胞外蛋白酶。通过两步法将主要的角蛋白分解丝氨酸蛋白酶纯化至同质。该酶的分子量为18,000，在pH值为6至9.5以及温度为40至70摄氏度范围内具有最佳活性。它对蛋白酶抑制剂的敏感性、对合成底物的特异性以及与灰色链霉菌蛋白酶B（SGPB）的显著高水平的NH2末端序列同源性表明，这种新酶命名为SAKase，与SGPB同源。我们用可溶性和纤维性底物（弹性蛋白、角蛋白和I型胶原蛋白）测试了SAKase的活性，发现与SGPB和蛋白酶K相比，它对角蛋白底物具有非常高的特异性。
