Extraction and Partial Characterization of A Lectin from Agaricus bisporus Strain AS2796

A lectin was extracted and purified from the fruiting bodies of Agaricus bisporus strain 2796.The procedures included PBS extraction followed by precipitation with 40%-60%(NH4)2SO4 and filtration with DEAE-Sepharose fast flow ion-exchange chromatography and Sephadex G-100 gel filtration chromatography.The purified protein showed a band in SDS-PAGE with the subunit molecular weight of 15.7kDa.The relative molecular mass of the AS2796 lectin was 64.1kDa,as determined by the gel filtration on a Sephadex G-100 column.Four different isoelectric forms with pIs of 6.62,5.92,5.69 and 5.57 were separated by IEF-PAGE.The AS2796 lectin was stable under high temperatures.Its agglutinating activity did not decline significantly after heating at 80℃ for 10 minutes,and maintained at high level at pH 3.0-10.0.In addition,the activity was not found to be divalent metal ion-dependent.