Purification and preliminary characterization of a cold-adapted extracellular proteinase from Trichoderma atroviride.
Eleven cold-tolerant Trichoderma isolates were screened for the production of proteolytic activities at 10 degrees C. Based on the activity profiles determined with paranitroanilide substrates at 5 degrees C, strain T221 identified as Trichoderma atroviride was selected for further investigations. The culture broth of the strain grown at 10 degrees C in casein-containing culture medium was concentrated by lyophilization and subjected to gel filtration, which was followed by chromatofocusing of the fraction showing the highest activity on N-benzoyl-Phe-Val-Arg-paranitroanilide. The purified enzyme had a molecular weight of 24 kDa, an isoelectric point of 7.3 and a pH optimum of 6.2. The temperature optimum of 25 degrees C and the low thermal stability suggested that it is a true cold-adapted enzyme. Substrate specificity data indicate that the enzyme is a proteinase with a preference for Arg or Lys at the P1 position. The effect of proteinase inhibitors suggests that the enzyme has a binding pocket similar to the one present in trypsin.
Kredics
L
L
Department of Microbiology, Faculty of Sciences and Informatics, University of Szeged, Szeged, Hungary.
Terecskei
Kata
K
Antal
Zsuzsanna
Z
Szekeres
A
A
Hatvani
L
L
Manczinger
L
L
Vágvölgyi
Cs
C
D000064:Acclimatization; D003080:Cold Temperature; D005656:Fungal Proteins / Q000378:metabolism; D007700:Kinetics; D010447:Peptide Hydrolases / Q000235:genetics / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D011480:Protease Inhibitors / Q000494:pharmacology; D013816:Thermodynamics; D014242:Trichoderma / Q000201:enzymology* / Q000235:genetics
D005656:Fungal Proteins; D011480:Protease Inhibitors; D010447:Peptide Hydrolases