@article{oai:kanazawa-u.repo.nii.ac.jp:00010420,
 author = {Saito-Otsuka, Kaori and Kurose, Shinji and Tsujino, Yoshio and Osakai, Toshiyuki and Kataoka, Kunishige and Sakurai, Takeshi and Tamiya, Eiichi},
 issue = {2},
 journal = {Journal of Bioscience and Bioengineering},
 month = {Feb},
 note = {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. © 2012 The Society for Biotechnology, Japan},
 pages = {159--167},
 title = {Electrochemical characterization of a unique, "neutral" laccase from Flammulina velutipes},
 volume = {115},
 year = {2013}
}