A laccase with antiproliferative activity against tumor cells from an edible mushroom, white common Agrocybe cylindracea

A laccase, with HIV-1 reverse transcriptase inhibitory activity (IC50 = 12.7 μM) and antiproliferative activity against HepG2 cells (IC50 = 5.6 μM) and MCF7 cells (IC50 = 6.5 μM), was purified from fresh fruiting bodies of the edible white common Agrocybe cylindracea mushroom. The laccase, which had a novel N-terminal sequence, displayed a molecular mass of 58 kDa within the range reported for most other mushroom laccases. The purification protocol entailed ion exchange chromatography on DEAE-cellulose, SP-Sepharose, and Q-Sepharose and gel filtration on Superdex 75. The laccase was adsorbed on DEAE-cellulose and Q-Sepharose, but unadsorbed on SP-Sepharose. Its optimum pH was pH 3–4 and its optimum temperature was 50 °C. The activity of the isolated laccase differed from one substrate to another. The ranking was ABTS > N,N-dimethyl-1,4-phenylenediamine > hydroquinone > catechol > 2-methylcatechol > pyrogallol.