面包树果实凝集素的提取纯化及理化性质分析

建立面包树果实凝集素(frutalin,FTL)的提取纯化方案,并对FTL纯品进行部分理化性质分析。本试验以新鲜的面包树果实籽为材料,经Tris-HCl缓冲液浸提、过滤、硫酸铵沉淀和阳离子交换层析后超滤浓缩得FTL纯品,最后用纯品开展了糖抑制,热稳定性,pH稳定性和金属离子耐受性等试验。提取优化得到的最佳条件为:料液比1∶2(g:m L),浸提时间2 h,浸提温度50℃,硫酸铵饱和度70%,沉淀时间4 h。经阳离子交换层析后FTL回收率为22%。研究结果表明,FTL是一种热稳定性凝集素,在温度不超过60℃时,其凝血活性不受影响,并且不依赖于金属离子来发挥其凝血活性。本研究建立了一个简单高效的FTL分离纯化方案,并对FTL纯品做了部分理化性质研究,为FTL可能的生物医学应用提供研究基础。

Extraction,purification and physicochemical analysis of lectin from bread tree fruit

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.