Electrochemical characterization of lignin peroxidase from the white-rot basidiomycete Phanerochaete chrysosporium

Masafumi Oyadomari, Hiroaki Shinohara, Toru Johjima, Hiroyuki Wariishi, Hiroo Tanaka

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23 Citations (Scopus)

Abstract

Electrochemical analysis of lignin peroxidase (LiP) was performed using a pyrolytic graphite electrode coated with peroxidase-embedded tributylmethyl phosphonium chloride membrane. The formal redox potential of ferric/ferrous couples of LiP was -126mV (versus SHE), which was comparable with that of manganese peroxidase (MnP) and horseradish peroxidase (HRP). Yet, only LiP is capable of oxidizing non-phenolic substrates with a high redox potential. Since with decreasing pH, the redox potential increased, an incredibly low pH optimum of LiP as peroxidase at 3.0 or lower was proposed as the clue to explain LiP mechanisms. A low pH might be the key for LiP to possess a high redox potential. The pKa values for the distal His in peroxidases were calculated using redox data and the Nernst equation, to be 5.8 for LiP, 4.7 for MnP, and 3.8 for HRP. A high pKa value of the distal His might be crucial for LiP compound II to uptake a proton from the solvent. As a result, LiP is able to complete its catalytic cycle during the oxidation of non-proton-donating substrates. In compensation, LiP has diminished its reactivity toward hydrogen peroxide.

Original languageEnglish
Pages (from-to)291-297
Number of pages7
JournalJournal of Molecular Catalysis B: Enzymatic
Volume21
Issue number4-6
DOIs
Publication statusPublished - Feb 17 2003

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Bioengineering
  • Biochemistry
  • Process Chemistry and Technology

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