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Oxidatively stable maltopentaose-producing α-amylase from a deep-sea Bacillus isolate, and mechanism of its oxidative stability validated by site-directed mutagenesis ☆

Paper ID Volume ID Publish Year Pages File Format Full-Text
18357 42719 2006 8 PDF Available
Title
Oxidatively stable maltopentaose-producing α-amylase from a deep-sea Bacillus isolate, and mechanism of its oxidative stability validated by site-directed mutagenesis ☆
Abstract

An oxidatively stable liquefying α-amylase (Amy204) was found in the culture of a Bacillus isolate, named strain JAMB-204, from the deep-sea at a depth of about 6000 m. The enzyme activity was maintained almost completely even after 1-h incubation with 1.0 M of H2O2. The molecular mass deduced from sodium dodecyl sulfate-polyacrylamide gel electrophoresis was approximately 55 kDa. The enzyme had a high isoelectric point of 8.6. The specific activity of purified Amy204 was very high at approximately 4200 units/mg of protein at 60 °C and pH 6.5 when soluble potato starch was used as the substrate. This enzyme efficiently hydrolyzed various carbohydrates to yield maltopentaose, maltotriose, and maltose as the major end products after completion of the reaction. The gene for Amy204 encodes 513 amino acids including a signal peptide of 29 amino acids. Amy204 exhibited amino acid homology to other known α-amylases: 80.4% identity with the enzyme from a Cytophaga sp., 77.8% identity with the enzyme from Bacillus licheniformis, and 77.7% identity with the enzyme from Bacillus amyloliquefaciens. Mutagenesis studies showed that the oxidative stability of Amy204 resulted from the amino acid at position 198 being a non-oxidizable amino acid of leucine, unlike the other liquefying α-amylases that have methionines at the equivalent positions.

Keywords
BLA, α-amylase from B. licheniformis; G1, glucose; G2, maltose; G3, maltotriose; G4, maltotetraose; G5, maltopentaose; MES, 2-morpholinoethanesulphonic acidα-Amylase; Bacillus; Deep-sea; Homology modeling; Maltopentaose; Oxidative stability; Site-directed
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Oxidatively stable maltopentaose-producing α-amylase from a deep-sea Bacillus isolate, and mechanism of its oxidative stability validated by site-directed mutagenesis ☆
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Publisher
Database: Elsevier - ScienceDirect
Journal: Enzyme and Microbial Technology - Volume 39, Issue 6, 3 October 2006, Pages 1333–1340
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