白芸豆凝集素的分子稳定性和光谱性质研究

The molecular stability and the fluorescence spectra study of Phaseolus coccineus lectin

经缓冲液抽提、CM-Sepharose、DEAE-Sepharose离子交换及Sephacryl S-200分子筛层析,从白芸豆种子纯化得到白芸豆凝集素(Phaseolus coccineus lectin,PCL).SDS-PAGE和Sephacryl S-200凝胶过滤分析表明白芸豆凝集素是由两个30 kD的单体组成的分子量约为56 kD的同源二聚体蛋白.凝血活性结果表明白芸豆凝集素能凝集的兔血细胞和人ABO血型细胞,无血型专一性.其凝血活性在80℃以下和pH 3.0～10.0时保持稳定.脲、盐酸胍对PCL凝血活性的影响表明,随着变性剂浓度的升高,凝血活性逐渐丧失.不同温度、pH和不同浓度变性剂条件下PCL的荧光光谱分析表明PCL变性过程的阶段性.

A novel lectin was purified from seeds of Phaseolus coccineus L. （P. multiflorus willd. ） by ion exchange and gel filtration chromatographies on CM, DEAE-Sepharose and Sephacryl S-200. It was a dimeric protein of 56 kD consisting of 30 kD subunits as determined by gel filtration and SDS-PAGE. PCL can agglutinated rabbit erythrocytes, chook erythrocytes and human erythrocytes regardless of blood type. The hemagglutinating activity of Phaseolus coccineus lectin （PCL） was stable up to 80℃ and at pH values from 3.0 to 10.0. Effects of different denaturants on the hemagglutinating activity indicated the activity lost gradually corresponding to the addition of concentration of denaturant. The fluo- rescence spectra study on different temperature, pH and the concentration of denaturants indicate the process of denaturalization of Phaseolus coccineus lectin.