title: Characterization of solvent, detergent and oxidizing agent stable protease from isolated Antarctic marine Streptomyces sp. XE-1.
abstract: OBJECTIVE
  A polar marine actinobacterium (XE-1) was selected and used to produce a protease with special characteristics.
  
  
  METHODS
  The XE-1 was identified as Streptomyces based on morphological, biochemical and molecular characterizations (16S rRNA gene sequence analysis). The protease was purified by 3 purification steps, including ethanol precipitation, ion exchange and gel chromatography. Its apparent molecular mass was estimated by SDS-PAGE.
  
  
  RESULTS
  A solvent, detergent and oxidizing agent stable alkaline serine protease (with a low weight molecular, 14 kDa by SDS-PAGE) , secreted by strain XE-1, was purified and characterized. The protease was stable in the pH range between 5 and 10, with optimal pH 8.2 and optimal temperature 55 degrees C. K(m) and V(max) towards casein activity were 1.9 mg/mL and 973 U/mL, respectively. The protease was more active and stable in various hydrophilic organic solvents (such as dimethylformamid and toluene). Moreover, it was also active and stable in bleaching agents (such as hydrogen peroxide) ; and stable in denaturant agents (such as urea and guanidine hydrochloride) at the concentration from 0.2 mol/L to 4 mol/L, which were the new characteristics.
  
  
  CONCLUSIONS
  These biochemical characteristics suggest this enzyme has the potential value in numerous industrial applications.
authors.forename: Yannan
authors.initials: Y
authors.lastname: Xu
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Lu
authors.forename: Yingying
authors.initials: Y
authors.lastname: Xing
authors.forename: Tao
authors.initials: T
authors.lastname: Xi
mesh_terms: D000864:Antarctic Regions; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D010450:Endopeptidases / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D004795:Enzyme Stability; D007700:Kinetics; D008969:Molecular Sequence Data; D010802:Phylogeny; D012623:Seawater / Q000382:microbiology*; D013302:Streptomyces / Q000145:classification / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification*
chemical_list: D001426:Bacterial Proteins; D010450:Endopeptidases; C087822:alkaline protease