Laccase-like activity of nucleoside oxidase in the presence of nucleosides.

作者：Yoshikazu Isono, Masami HOSHINO · 发表于：Agricultural and Biological Chemistry · 年份：1989 · DOI：10.1271/bbb1961.53.2197 · 被引用次数：10 · 研究领域：Chemical Analysis and Environmental Impact、Cytomegalovirus and herpesvirus research、Neutrophil, Myeloperoxidase and Oxidative Mechanisms

Nucleoside oxidase that was purified to an electrophretically homogeneousstate catalyzed the oxidation of hydroquinone only in the presence of nucleosides simultaneously with the oxidation of nucleosides.From the identification of the reaction products and a chemical balance study, we concluded that the oxidation of hydroquinone proceeded by the following scheme: 2 hydroquinone + O2 ->2p-quinone + 2H2O.The enzyme also catalyzed the oxidation of various phenolic compounds and strongly colored substances were formed from phenolic compoundswith 4-aminoantipyrine in proportion to the amountof nucleosides.As described in earlier communications,1 ~3) we found a new enzyme that catalyzes the oxidation of nucleosides to nucleoside-5'-carboxylic acid via nucleoside-5'-aldehyde without a requirement for an exogenous co factor.The enzymewas purified from the cell-free extract of Pseudomonas maltophilia LB-86 by a procedure involving column chromatographies on DEAE-Toyopearl and gel filtration on Sephacryl S-200.The final preparation was homogeneous on polyacrylamide gel electrophoresis.The purified enzyme oxidized various nucleosides but not did attack nucleotides, bases, or ribose.During the investigation on this enzyme, we found that the enzyme catalyzes the oxidation of hydroquinone to pquinone.This oxidation reaction was identical with that of laccase (EC 1.10.3.2), but this activity of nucleoside oxidase appeared only in the presence of nucleoside.This paper describes an identifica...