Document Detail


Electrochemical characterization of a unique, "neutral" laccase from Flammulina velutipes.
MedLine Citation:
PMID:  23063242     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
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 O(2) 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 O(2)-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.
Authors:
Kaori Otsuka Saito; Shinji Kurose; Yoshio Tsujino; Toshiyuki Osakai; Kunishige Kataoka; Takeshi Sakurai; Eiichi Tamiya
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-10-10
Journal Detail:
Title:  Journal of bioscience and bioengineering     Volume:  -     ISSN:  1347-4421     ISO Abbreviation:  J. Biosci. Bioeng.     Publication Date:  2012 Oct 
Date Detail:
Created Date:  2012-10-15     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100888800     Medline TA:  J Biosci Bioeng     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Copyright Information:
Copyright © 2012 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.
Affiliation:
School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1292, Japan.
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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