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A new recombinant phosphotriesterase homology protein from Geobacillus caldoxylosilyticus TK4: An extremely thermo- and pH-stable esterase

Paper ID Volume ID Publish Year Pages File Format Full-Text
35303 45085 2009 8 PDF Available
Title
A new recombinant phosphotriesterase homology protein from Geobacillus caldoxylosilyticus TK4: An extremely thermo- and pH-stable esterase
Abstract

Phosphotriesterase homology protein (PHP) is a member of a recently discovered family of proteins related to phosphotriesterase. Phosphotriesterase is a hydrolytic, bacterial enzyme with unusual substrate specificity for synthetic organophosphate triesters, common constituents of chemical warfare agents and agricultural pesticides. PHP may belong to the family of proteins from which phosphotriesterase evolved. The PHP gene from the thermophilic bacterium Geobacillus caldoxylosilyticus TK4 was cloned and overexpressed in Escherichia coli with 6×His tag in the N-terminal. The recombinant protein was purified with nickel affinity chromatography and characterized in detail. The enzyme did not have any activity against paraoxon. The highest activities were observed with p-nitrophenyl acetate (pNPA) and p-nitrophenyl butyrate. pH and temperature optima were determined as 8.0 and 50 °C, respectively, with pNPA. The enzyme activity was not largely affected by the incubation of the enzyme at 50 °C in the different buffer solutions (pHs between 3.0 and 9.0) for 7 days. After the incubation at 90 °C for 7 days, G. caldoxylosilyticus TK4 PHP retained 62% of its original activity. The enzyme was also resistant to some metal ions and organic solvents. These results suggest that this is the first reported PHP having an extremely pH- and thermo-stable esterase activity.

Keywords
Cloning; Esterase; Geobacillus caldoxylosilyticus TK4; Phosphotriesterase; Phosphotriesterase homology protein
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A new recombinant phosphotriesterase homology protein from Geobacillus caldoxylosilyticus TK4: An extremely thermo- and pH-stable esterase
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Publisher
Database: Elsevier - ScienceDirect
Journal: Process Biochemistry - Volume 44, Issue 12, December 2009, Pages 1366–1373
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us