Komath S S, Nadimpalli S K, Swamy M J
School of Chemistry, University of Hyderabad, India.
Biochem Mol Biol Int. 1996 May;39(2):243-52. doi: 10.1080/15216549600201251.
The galactose-specific lectin present in the seeds of snake gourd (Trichosanthes anguina) was purified in high yield by affinity chromatography on cross-linked guar gum. The purified snake gourd seed lectin (SGSL) yielded a single symmetrical peak on gel filtration with an M(r) of 62 kDa and gave a single band in PAGE under non-denaturing conditions. In SDS-PAGE, SGSL gave a single band of M(r) 53 kDa in the absence of beta-mercaptoethanol, and two bands of M(r) 32 and 23 kDa in its presence, indicating that the lectin is a heterodimer in which the subunits are linked by a disulphide bridge. The lectin gave a single precipitin line in immunodiffusion experiments with antiserum raised against the purified SGSL. No cross-reactivity was found between SGSL and antiserum raised against the Momordica charantia lectin and vice versa, suggesting that the two lectins are antigenically dissimilar. Haemagglutination-inhibition data show that Me beta D-Gal is the best monosaccharide inhibitor of SGSL and indicate that an equatorial hydroxyl at C-2 and axial hydroxyl at C-4 in the pyranose form are important binding loci for the lectin.
通过交联瓜尔胶亲和层析法，以高产率纯化了蛇瓜（Trichosanthes anguina）种子中存在的半乳糖特异性凝集素。纯化后的蛇瓜种子凝集素（SGSL）在凝胶过滤中产生一个单一的对称峰，分子量为62 kDa，在非变性条件下的聚丙烯酰胺凝胶电泳（PAGE）中呈现一条带。在十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（SDS-PAGE）中，在没有β-巯基乙醇的情况下，SGSL呈现一条分子量为53 kDa的带，而在有β-巯基乙醇的情况下，呈现两条分子量分别为32 kDa和23 kDa的带，这表明该凝集素是一种异二聚体，其中亚基通过二硫键连接。在用针对纯化后的SGSL产生的抗血清进行的免疫扩散实验中，该凝集素产生一条单一的沉淀线。未发现SGSL与针对苦瓜凝集素产生的抗血清之间有交叉反应，反之亦然，这表明这两种凝集素在抗原性上不同。血凝抑制数据表明，甲基-β-D-半乳糖是SGSL的最佳单糖抑制剂，并表明吡喃糖形式中C-2位的赤道羟基和C-4位的轴向羟基是该凝集素的重要结合位点。
