Abstract: Laccase is a main member of the multi-copper oxidase family, which can catalyze the oxidation of a variety of phenols andaromatic compounds, so it has great industrial application potential. Although some progress has been made in the research and appli-cation of laccase, it is mainly focused on plant and fungal laccase, and less research on bacterial laccase. In this study, a laccase geneNCgl0908was isolated fromCorynebacteriumglutamicum, with a total length of 1 542 bp and encoding 513 amino acids. Its amino acid sequence was compared with several identified bacterial and fungal laccases, and the four copper ion binding sites were found to behighly conserved. Therefore,NCgl0908is speculated as a new laccase gene.NCgl0908was cloned into the expression vector pColdⅡ and induced to express inE.coliBL21. The expression product was purified by nickel column affinity chromatography. Its laccase activi-ty and enzyme kinetic parameters were measured by using ABTS as a substrate, and the result showed that the laccase activity was 25. 4U / mL,Kmwas 2.22 ×10-4mol /L, andVmaxwas 2.432 ×10-6mol /(L·min).

Key words: Corynebacteriumglutamicum, bacterial laccase, extracellular expression, enzyme kinetic parameters;Escherichiacoli