Abstract: To establish the extraction and purification process of frutalin from Artocarpus incisa (breadfruit) seeds,and then analyze the physicochemical properties of the purified frutalin.In this experiment,Artocarpus incisa (breadfruit) seeds were used as materials.The crude frutalin was extracted from fresh breadfruit seeds with Tris-HCl buffer and precipitated with ammonium sulfate,which was further purified with cation exchange chromatography and ultrafiltration.After purified frutalin obtained,several physicochemical properties,including sugar inhibition,thermostability,pH stability and metal ion tolerance,were tested.The optimal extraction condition of frutalin was obtained as follows:the ratio of material to liquid was 1∶2 (g∶mL),the extraction time was 2 h,the extraction temperature was 50 ℃,the saturation of ammonium sulfate was 70% and the precipitation time is 4 h.The yield of purified frutalin was 22%.The results show that FTL is a kind of thermostable lectin,and its haemagglutinating activity will not damage when the temperature keep no high than 60 ℃,and the haemagglutinating activity does not effected by common metal ions.In a word,a simple and effective separation and purification protocol of frutalin has been set up,followed with a series of physicochemical properties analysis with the purified frutalin.All mentioned above results may pave the way for the biomedical application of frutalin.

Key words: breadfruit, lectin, isolation and purification, haemagglutinating activity, physicochemical properties