Iodide Oxidation by a Novel Multicopper Oxidase from the Alphaproteobacterium Strain Q-1

• DOI: 10.1128/aem.00084-12
• Publication Date: 2012-03-24T07:34:07Z
• Authors: Mio Suzuki; Yoshifumi Eda; Shiaki Ohsawa; Yu Kanesaki; Hirofumi Yoshikawa; Kan Tanaka; Yasuyuki Muramatsu; Jun Yoshikawa; Ikuo Sato; Takaaki Fujii; Seigo Amachi
• Keywords: Multicopper oxidase; Strain (injury)

Alphaproteobacterium strain Q-1 is able to oxidize iodide (I(-)) molecular iodine (I(2)) by an oxidase-like enzyme. One of the two isoforms iodide-oxidizing enzyme (IOE-II) produced this was excised from a native polyacrylamide gel, eluted, and purified. IOE-II appeared as single band (51 kDa) showed significant in-gel activity in sodium dodecyl sulfate-polyacrylamide gel electrophoresis without heat treatment. However, at least bands with much higher masses (150 230 were observed treatment (95°C, 3 min). inhibited NaN(3), KCN, EDTA, copper chelator, o-phenanthroline. In addition iodide, activities toward phenolic compounds such syringaldazine, 2,6-dimethoxy phenol, p-phenylenediamine. contained atoms prosthetic groups had UV/VIS absorption peaks 320 590 nm. Comparison several internal amino acid sequences obtained trypsin-digested draft genome sequence revealed that products open reading frames (IoxA IoxC), predicted 62 71 kDa, are involved oxidation. Furthermore, subsequent tandem mass spectrometric analysis repeatedly detected peptides IoxA IoxC high coverage (32 40%). homology family multicopper oxidases included four copper-binding regions highly conserved among various oxidases. These results suggest oxidase it may occur multimeric complex which proteins IoxC) associated.