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A laccase with inhibitory activity against HIV-1 reverse transcriptase from the mycorrhizal fungus Lepiota ventriosospora

Zhang, Guo-Qing, Chen, Qing-Jun, Wang, He-Xiang, Ng, Tzi Bun
Journal of Molecular Catalysis. B, Enzymatic 2013 v.85-86 pp. 31-36
Human immunodeficiency virus 1, Lepiota, RNA-directed DNA polymerase, catalytic activity, fruiting bodies, inhibitory concentration 50, ion exchange chromatography, laccase, molecular weight, mycorrhizal fungi, pH, temperature
An isolation procedure that comprised three ion-exchange chromatography steps on DEAE-cellulose, CM-cellulose, and Q-Sepharose, and one gel-filtration step by fast protein liquid chromatography on Superdex 75 was utilized to isolate a laccase with a molecular mass of 65kDa from fresh fruiting bodies of the mycorrhizal fungus Lepiota ventriosospora. Laccase activity was adsorbed on both DEAE-cellulose and Q-Sepharose but unadsorbed on CM-cellulose. An overall 26.3-fold of purification was obtained. The enzyme demonstrated an optimum temperature at 60°C and an optimum pH 4.0. The purified laccase was quite stable at pH range of 3.6–4.4, but only 17.8% of total activity left after 1h incubating at 60°C. The ranking of its degradative activity toward aromatic substrates was catechol>hydroquinone>ABTS>2,6-dimethoxy-phenol. It demonstrated the highest inhibitory activity toward HIV-1 reverse transcriptase with an IC50 value of 0.60μM among fungal laccaes reported up to now.