title: Enzymatic activity of a subtilisin homolog, Tk-SP, from Thermococcus kodakarensis in detergents and its ability to degrade the abnormal prion protein.
abstract: BACKGROUND
  Tk-SP is a member of subtilisin-like serine proteases from a hyperthermophilic archaeon Thermococcus kodakarensis. It has been known that the hyper-stable protease, Tk-SP, could exhibit enzymatic activity even at high temperature and in the presence of chemical denaturants. In this work, the enzymatic activity of Tk-SP was measured in the presence of detergents and EDTA. In addition, we focused to demonstrate that Tk-SP could degrade the abnormal prion protein (PrPSc), a protease-resistant isoform of normal prion protein (PrPC).
  
  
  RESULTS
  Tk-SP was observed to maintain its proteolytic activity with nonionic surfactants and EDTA at 80°C. We optimized the condition in which Tk-SP functions efficiently, and demonstrated that the enzyme is highly stable in the presence of 0.05% (w/v) nonionic surfactants and 0.01% (w/v) EDTA, retaining up to 80% of its activity. Additionally, we also found that Tk-SP can degrade PrPSc to a level undetectable by western-blot analysis.
  
  
  CONCLUSIONS
  Our results indicate that Tk-SP has a great potential for technological applications, such as thermo-stable detergent additives. In addition, it is also suggested that Tk-SP-containing detergents can be developed to decrease the secondary infection risks of transmissible spongiform encephalopathies (TSE).
authors: Laboratory of Biological Chemistry, Department of Biomolecular Chemistry, Kyoto Prefectural University, Kyoto, Japan.
authors: Azumi
authors: A
authors: Hirata
authors: Yuki
authors: Y
authors: Hori
authors: Yuichi
authors: Y
authors: Koga
authors: Jun
authors: J
authors: Okada
authors: Akikazu
authors: A
authors: Sakudo
authors: Kazuyoshi
authors: K
authors: Ikuta
authors: Shigenori
authors: S
authors: Kanaya
authors: Kazufumi
authors: K
authors: Takano
mesh_terms: D019843:Archaeal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D003902:Detergents / Q000737:chemistry*; D004492:Edetic Acid / Q000737:chemistry; D004926:Escherichia coli / Q000378:metabolism; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D011328:Prions / Q000378:metabolism*; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics; D020860:Subtilisin / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D019712:Thermococcus / Q000201:enzymology*
chemical_list: D019843:Archaeal Proteins; D003902:Detergents; D011328:Prions; D011994:Recombinant Proteins; D004492:Edetic Acid; D020860:Subtilisin