RRC ID 57512
Author Shiroyama K, Kawasaki Y, Unno Y, Amachi S.
Title A putative multicopper oxidase, IoxA, is involved in iodide oxidation by Roseovarius sp. strain A-2.
Journal Biosci Biotechnol Biochem
Abstract Roseovarius sp. strain A-2 is an aerobic heterotrophic bacterium with a capacity for oxidizing iodide ion (I(-)) to form molecular iodine (I2). In this study, iodide-oxidizing enzyme of strain A-2 was characterized. The enzyme was an extracellular protein, and Cu(2+) ion significantly enhanced the enzyme activity in the culture supernatant. When iodide was used as the substrate, the crude enzyme showed Km and Vmax values of 4.78 mM and 25.1 U mg(-1), respectively. The enzyme was inhibited by NaN3, EDTA, KCN, and o-phenanthroline, and also had significant activities toward p-phenylenediamine and hydroquinone. Tandem mass spectrometric analysis of an active band excised from SDS-PAGE gel revealed that at least two proteins are involved in the enzyme. One of these proteins was closely related with IoxA, a multicopper oxidase previously found as a component of iodide-oxidizing enzyme of Alphaproteobacterium strain Q-1. Furthermore, a terrestrial bacterium Rhodanobacter denitrificans 116-2, which possesses an ioxA-like gene in its genome, was found to oxidize iodide. These results suggest that IoxA catalyzes the oxidation of iodide in phylogenetically distinct bacteria.
Volume 79(11)
Pages 1898-905
Published 2015-1-1
DOI 10.1080/09168451.2015.1052767
PMID 26041311
MeSH Bacterial Proteins / genetics* Bacterial Proteins / metabolism* Copper / chemistry Copper / metabolism Iodides / chemistry Iodides / metabolism* Ions / chemistry Oxidation-Reduction Oxidoreductases / chemistry Oxidoreductases / genetics* Oxidoreductases / metabolism* Phylogeny RNA, Ribosomal, 16S / genetics Rhodobacteraceae / enzymology*
IF 1.297
Times Cited 4
General Microbes JCM 17641, JCM 17642