KMID : 0545120100200071069
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Journal of Microbiology and Biotechnology 2010 Volume.20 No. 7 p.1069 ~ p.1076
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Purification and characterization of a laccase from the edible wild mushroom Tricholoma mongolicum
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Miao Li
Guoqing Zhang Hexiang Wang Tzibun Ng
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Abstract
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A novel laccase from Tricholoma mongolicum was purified by using a procedure which entailed ion exchange chromatography on DEAE-cellulose, CM-cellulose, Q-Sepharose, and FPLC-gel filtration on Superdex 75. The purified enzyme was obtained with a specific activity of 1480 U (mg protein)-1 and a final yield of 15%. It was found to be a monomeric protein with a molecular mass of 66 kDa as estimated by sodium dodecyl sulphate-polyacrylamide gel electrophoresis. Its N-terminal amino acid sequence was GIGPVADLYVGNRIL, similar to some but different other mushroom laccase. The optimum pH and temperature for the purified enzyme were pH 2 to pH 3 and 30 ¡ÆC, respectively. It displayed a low Km toward 2,7¡Ç-azinobis (3-ethylbenzothiazolone-6-sulfonic acid) diammonium salt (ABTS) and high Kcat/Km values. The purified laccase oxidized a wide range of lignin-related phenols, but exerted maximal activity on ABTS. It was significantly inhibited by Hg2+ ions, and remarkably stimulated by Cu2+ ions. It inhibited HIV-1 reverse transcriptase and proliferation of hepatoma HepG2 cells and breast cancer MCF7 cells with an IC50 of 0.65 ¥ìM, 1.4 ¥ìM, and 4.2 ¥ìM, respectively, indicating that it is also an antipathogenic protein.
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KEYWORD
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Laccase, Tricholoma mongolicum, Purification, Characterization
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