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Electrochemical characterization of a unique, “neutral” laccase from Flammulina velutipes

Paper ID Volume ID Publish Year Pages File Format Full-Text
20829 43193 2013 9 PDF Available
Title
Electrochemical characterization of a unique, “neutral” laccase from Flammulina velutipes
Abstract

The flac1 gene consisted of 1488 bases encodes a novel laccase (Flac1) from Flammulina velutipes. The deduced amino acid sequence of Flac1 with 496 amino acids shows 58–64% homologies with other fungal laccases. The recombinant Flac1 (rFlac1) was heterologously expressed in Pichia pastoris, with sugars of approximately 4 kDa attached on the protein molecule, which has the calculated molecular mass of 53,532 Da. rFlac1 was shown to be a multi-copper oxidase from spectroscopies. The optimum pHs of rFlac1 for oxidations of 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), p-phenylenediamine, and o-aminophenol, were 5.0, 5.0, and 6.0–6.5, respectively, showing higher pH values than those from many other fungal laccases. The slightly acidic or neutral optimum pH that is not strongly dependent on substrates is a unique property of rFlac1. Effective O2 reduction was realized by the direct electron transfer of rFlac1 at a highly oriented pyrolytic graphite electrode modified with fine carbon particles (Ketjen Black) in O2-saturated solution. The pHs showing the maximum ΔE°′ [= E°′(enzyme) − E°′(substrate)] coincided well with the optimum pHs shown by rFlac1 under steady-state conditions. The present electrochemical results of rFlac1 indicate that ΔE°′ is one of the primary factors to determine the activity of multi-copper oxidases.

Keywords
Laccase; Flammulina velutipes; Heterologous expression; Direct electron transfer; Redox potential; Optimum pH
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Electrochemical characterization of a unique, “neutral” laccase from Flammulina velutipes
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Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Bioscience and Bioengineering - Volume 115, Issue 2, February 2013, Pages 159–167
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