Purification and characterization of a laccase with inhibitory activity toward HIV-1 reverse transcriptase and tumor cells from an edible mushroom (pleurotus cornucopiae)

Abstract

A 66-kDa laccase, with an N-terminal sequence different from those of other mushroom laccases, was purified from fresh fruiting bodies of the edible mushroom Pleurotus cornucopiae by using affinity chromatography on Affi-gel blue gel, ion exchange chromatography on Mono Q and gel filtration on Superdex 75. The procedure resulted in a 16-fold purification and a specific enzyme activity of 17.3 U mg -1. The optimum pH and temperature for the purified laccase were pH 4 and 40°C, respectively. This laccase inhibited proliferation of murine leukemia cell line L1210 and human hepatoma cell line HepG2, and reduced the activity of HIV-1 reverse transcriptase with an IC 50 of 22 μM. There was neither mitogenic activity toward mouse splenocytes, nor hemagglutinating/hemolytic activity toward rabbit erythrocytes. This study yielded information about the potentially exploitable activities of P. cornucopiae laccase. © 2010 Bentham Science Publishers Ltd.