Purification and characterization of a keratinolytic serine proteinase from Streptomyces albidoflavus. |
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| Authors: | P Bressollier F Letourneau M Urdaci B Verneuil |
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| Institution: | Laboratoire de Génie Enzymatique et Biovalorisation (Unité du Laboratoire de Chimie des Substances Naturelles), I.U.T., Département de Génie Biologique, Limoges, France. |
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| Abstract: | 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. |
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