Isolation and purification of a lectin from roots of Astragalus membranaceus / 中草药

Objective To isolate and purify a lectin from the roots of Astragalus membranaceus.Methods The protein was purified using a combination of 20%—60% ammonium sulfate fraction and ConA-Sepharose 4B affinity chromatography.Results The purified protein appeared as a single band with molecular mass of 3.15?104 on SDS-PAGE and the relative molecular mass was estimated by gel filtration on a calibrated Superdex 75 column with apparent molecular weight of 3.35?104.This lectin was a glycoprotein with a neutral carbohydrate content of 10.7%.Conclusion A lectin is isolated and purified from the roots of A.membranaceus for the first time.It is a monomer glycoprotein and its specific activity is 391.9 U/mg.