title: Biochemical and molecular characterisation of Tetrahymena thermophila extracellular cysteine proteases.
abstract: BACKGROUND
  Over the last decades molecular biologic techniques have been developed to alter the genome and proteome of Tetrahymena thermophila thereby providing the basis for recombinant protein expression including functional human enzymes. The biotechnological potential of Tetrahymena has been proved in numerous publications, demonstrating fast growth, high biomass, fermentation in ordinary bacterial/yeast equipment, up-scalability, existence of cheap and chemical defined media. For these reasons Tetrahymena offers promising opportunities for the development of a high expression system. Yet optimised high yield strains with protease deficiency such as commonly used in yeast and bacterial systems are not available.
  
  
  RESULTS
  This work presents the molecular identification of predominant proteases secreted into the medium by Tetrahymena thermophila. A one-step purification of the proteolytic enzymes is described.
  
  
  CONCLUSIONS
  The information provided will allow silencing of protease activity by either knock out methods or by Tetrahymena specific antisense-ribosome-techniques. This will facilitate the next step in the advancement of this exciting organism for recombinant protein production.
authors.affiliation: Cilian AG, Johann-Krane-Weg 42, Muenster D-48149, Germany. herrmann@cilian.de
authors.forename: Lutz
authors.initials: L
authors.lastname: Herrmann
authors.forename: Michael
authors.initials: M
authors.lastname: Erkelenz
authors.forename: Ingo
authors.initials: I
authors.lastname: Aldag
authors.forename: Arno
authors.initials: A
authors.lastname: Tiedtke
authors.forename: Marcus W W
authors.initials: MW
authors.lastname: Hartmann
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001709:Biotechnology / Q000379:methods; D003546:Cysteine Endopeptidases / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification*; D015853:Cysteine Proteinase Inhibitors / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D018503:Genome, Protozoan; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008969:Molecular Sequence Data; D015800:Protozoan Proteins / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification*; D016415:Sequence Alignment; D016808:Tetrahymena thermophila / Q000201:enzymology* / Q000235:genetics
chemical_list: D015853:Cysteine Proteinase Inhibitors; D015800:Protozoan Proteins; D003546:Cysteine Endopeptidases