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Cloning, expression and characterization of highly thermo- and pH-stable maltogenic amylase from a thermophilic bacterium Geobacillus caldoxylosilyticus TK4

Paper ID Volume ID Publish Year Pages File Format Full-Text
35598 45098 2010 8 PDF Available
Title
Cloning, expression and characterization of highly thermo- and pH-stable maltogenic amylase from a thermophilic bacterium Geobacillus caldoxylosilyticus TK4
Abstract

Maltogenic amylases (MAases), a subclass of cyclodextrin (CD)-hydrolyzing enzymes, belong to glycoside hydrolase family 13. A gene corresponding to MA in Geobacillus caldoxylosilyticus TK4 (GcaTK4MA) was cloned into pET28a(+) vector and expressed in Escherichia coli with 6xHis-tag at the N-terminus. Herein, we report on the biochemical properties of a new thermo- and pH-stable MA. GcaTK4MA has similar properties those of other MAases in terms of the primary structure, preference for CD over starch and having an extra domain at its N- and C-terminals. The recombinant protein was purified efficiently by using one-step nickel affinity chromatography. The purified enzyme exhibited optimal activity for β-CD hydrolysis at 50 °C and pH 7.0. When the enzyme was separately incubated at 4 °C and 50 °C in the buffer solutions (pH 3.0–9.0) up to 7 days, it was seen that the enzyme had the higher stability at 50 °C than 4 °C. The enzyme retained about 80% of its original activity when it was incubated at 50 °C for 7 days. The enzyme activity was significantly inhibited by SDS and EDTA at the final concentration of 1%. These results suggest that this is the first reported MA having an extremely pH- and thermal stabilities.

Keywords
Characterization; Cloning; Geobacillus caldoxylosilyticus TK4; Maltogenic amylase; Thermophilic
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Cloning, expression and characterization of highly thermo- and pH-stable maltogenic amylase from a thermophilic bacterium Geobacillus caldoxylosilyticus TK4
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Publisher
Database: Elsevier - ScienceDirect
Journal: Process Biochemistry - Volume 45, Issue 6, June 2010, Pages 821–828
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