A novel laccase with urate oxidation activity from Lysobacter sp. T-15.
A unique urate-oxidizing enzyme was identified in a bacterium, strain T-15. Based on its phylogenetic, physiological and biochemical properties, strain T-15 was deemed to be a novel species within the genus Lysobacter. The enzyme expressed in Lysobacter sp. T-15 was composed of 592 amino acids and contained four consensus copper-binding sites, and the recombinant enzyme was, at least in this study, speculated to have three Cu ions per subunit. The primary structure of the enzyme was 33% identical to Marinomonas mediterranea polyphenol oxidase, but it showed no significant similarity to any known urate oxidase. With urate as the substrate, the catalytic efficiency (k(cat)/K(m)) of recombinant enzyme was 4.0 × 10(2) s(-)(1)mM(-)(1), and it was not inhibited by xanthine, a strong urate oxidase inhibitor. The enzyme also showed activity toward 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid), 2,6-dimethoxyphenol and bilirubin, with catalytic efficiencies of 4.9 × 10(2), 1.1 × 10(2) and 3.6 × 10(3) s(-)(1)mM(-)(1), respectively. We deemed the enzyme would be a member of laccase from its broad substrate specificity. However, typical laccase and other multi-copper oxidases such as bilirubin oxidase and ascorbate oxidase seldom exhibit urate oxidation activity. These results would expand the laccase substrate range to include urate.
Tamaki
Hideyuki
H
Institute for Biological Resources and Functions, National Institute of Advanced Industrial Science and Technology (AIST), Central 6, Higashi 1-1-1, Tsukuba, Ibaraki, Japan.
Matsuoka
Takeshi
T
Yasuda
Yuko
Y
Hanada
Satoshi
S
Kamagata
Yoichi
Y
Nakamura
Kazunori
K
Sakasegawa
Shin-Ichi
S
D000595:Amino Acid Sequence; D000818:Animals; D001426:Bacterial Proteins / Q000145:classification / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D003300:Copper / Q000378:metabolism; D042845:Laccase / Q000145:classification / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D053528:Lysobacter / Q000201:enzymology*; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D010802:Phylogeny; D016415:Sequence Alignment; D014527:Uric Acid / Q000378:metabolism*
D001426:Bacterial Proteins; D014527:Uric Acid; D003300:Copper; D042845:Laccase