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Production, purification and partial enzymatic and molecular characterization of a laccase from the wood-rotting ascomycete Xylaria polymorpha

Paper ID Volume ID Publish Year Pages File Format Full-Text
18088 42711 2007 9 PDF Available
Title
Production, purification and partial enzymatic and molecular characterization of a laccase from the wood-rotting ascomycete Xylaria polymorpha
Abstract

The hard wood-colonizing ascomycete Xylaria polymorpha, that is seemingly lacking peroxidases, produces laccase as sole ligninolytic oxidoreductase. The fungus secreted the enzyme preferably during the growth in complex media based on tomato juice. Addition of 2,5-xylidine considerably stimulated laccase production (up to 14,000 U l−1). The enzyme was purified to homogeneity by anion exchange and size exclusion chromatography and characterized by biochemical and molecular methods. Xylaria laccase has a molecular mass of 67 kDa, a pI of 3.1 and an absorption maximum at 605 nm that is characteristic for blue copper proteins. It oxidized all typical laccase substrates including ABTS, 2,6-dimethoxyphenol, guaiacol as well as syringaldazine (catalytic efficiencies 3 × 103 to 7 × 104 M−1 s−1). The deduced amino acid sequence of one amplified laccase gene sequence between the copper binding regions 1 and 3 showed a high level of identity to some other laccases from ascomycetes. Furthermore, the sequence of an internal peptide fragment of the purified laccase was identical with an amino acid sequence deduced from the nucleotide sequence of the laccase gene. Xylaria laccase was found to oxidize a non-phenolic β-O-4 lignin model compound in presence of 1-hydroxybenzotriazole into the corresponding keto-form. The results of this study show that – in addition to ligninolytic basidiomycetes – also wood-dwelling ascomycetes can produce high titers of laccase that may be involved in the oxidation of lignin.

Keywords
Xylariaceae; Soft-rot; Phenol oxidase; Lignin model compound; Redox mediator; Copper binding region
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Production, purification and partial enzymatic and molecular characterization of a laccase from the wood-rotting ascomycete Xylaria polymorpha
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Publisher
Database: Elsevier - ScienceDirect
Journal: Enzyme and Microbial Technology - Volume 41, Issues 6–7, 1 November 2007, Pages 785–793
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