title: Copper ion-stimulated McoA-laccase production and enzyme characterization in Proteus hauseri ZMd44.
abstract: The novel bioelectricity-generating bacterium of Proteus hauseri ZMd44 has been first identified to produce McoA-laccase (EC 1.10.3.2) induced by copper sulphate. The optimal concentration of copper is 3 mM as supplementation at the beginning of culture or early exponential growth phase, during which laccase is predominantly synthesized. Moreover, the whole cellular and intracellular activities of laccase increase in the degrees of inducible copper concentrations. A possible mechanism for this phenomenon is that copper ions enhance the laccase genetic transcription level during the laccase synthesis thus granting this strain in copper tolerance. McoA-laccase belongs to typical type 1 (T1) Cu site laccase by electron paramagnetic resonance (EPR) analysis of intracellular enzyme. From our results, the optimal temperature and pH are 60°C and pH 2.2, respectively. The kinetic profiles show that this enzyme is stable under 50°C and in the slightly acidic environment, making it a potentially useful enzyme in dye decolorization, paper-pulp bleaching and bioremediation industries.
authors.affiliation: Department of Chemical and Biochemical Engineering, Xiamen University, Xiamen, China.
authors.forename: Xuesong
authors.initials: X
authors.lastname: Zheng
authors.forename: I-Son
authors.initials: IS
authors.lastname: Ng
authors.forename: Chiming
authors.initials: C
authors.lastname: Ye
authors.forename: Bor-Yann
authors.initials: BY
authors.lastname: Chen
authors.forename: Yinghua
authors.initials: Y
authors.lastname: Lu
mesh_terms: D002412:Cations; D003300:Copper / Q000737:chemistry*; D019327:Copper Sulfate / Q000494:pharmacology; D004578:Electron Spin Resonance Spectroscopy; D042845:Laccase / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism*; D011511:Proteus / Q000201:enzymology* / Q000254:growth & development
chemical_list: D002412:Cations; D003300:Copper; D042845:Laccase; D019327:Copper Sulfate