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Purification, characterization and thermodynamics of antifungal protease from Streptomyces sp. A6
Author(s) -
Singh Anil Kumar,
Chhatpar Hari S.
Publication year - 2011
Publication title -
journal of basic microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.58
H-Index - 54
eISSN - 1521-4028
pISSN - 0233-111X
DOI - 10.1002/jobm.201000310
Subject(s) - serine protease , protease , chemistry , urea , enzyme , streptomyces , enzyme kinetics , enzyme assay , stereochemistry , chromatography , active site , nuclear chemistry , biochemistry , biology , bacteria , genetics
Abstract A 20 kDa antifungal serine protease from Streptomyces sp. A6 was purified to 34.56 folds by gel permeation chromatography. The enzyme exhibited highest activity at neutral to near alka‐ line pH 7–9 and 55 °C. Neutral surfactant triton X‐100 enhanced the activity by 4.12 fold. The protease activity also increased (109.9–119%) with increasing concentration of urea (2–8 mole/l). The enzyme was identified as serine protease with 67% similarity to SFase 2 of Streptomyces fradiae by MALDI‐LC‐MS/MS analysis. Determination of kinetic constants k m , V max , k cat and k cat / k m suggested higher affinity of enzyme for N‐Suc‐Ala‐Ala‐Val‐Ala‐ p NA (synthetic substrate for chymotrypsin activity). The enzyme was highly stable at temperature prevailing under field conditions (40 °C) as apparent from K d and t 1/2 values, 0.0065 and 106.75 min, respectively and high Δ G * and negative Δ S * values, 87.17 KJ/mole and –126.95 J/mole, respectively. Thermal stability and increased activity of protease in presence of commonly used chemical fertilizer, urea, suggested its feasibility for agricultural applications. The present study is the first report on thermodynamic and kinetic properties of an antifungal protease from Streptomyces sp. A6. The study reflects potential of this enzyme for biocontrol of fungal plant pathogens. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)