Pleurostrin, an antifungal peptide from the oyster mushroom

A 7 kDa peptide, with inhibitory activity on mycelial growth in the fungi Fusaerium oxysporum, Mycosphaerella arachidicola and Physalospora piricola, was isolated from fresh fruiting bodies of the oyster mushroom. The isolation procedure entailed extraction with an aqueous buffer, ion exchange chromatography on DEAE-cellulose, affinity chromatography on Affi-gel blue gel and gel filtration by fast protein liquid chromatography on Superdex 75. The protein was unadsorbed on DEAE-cellulose and adsorbed on Affi-gel blue gel. It demonstrated an N-terminal sequence different from known antifungal proteins and peptides.