Phaseolus lunatus Linn vel aff的种子中A型血专一性凝集素的研究

用亲和层析法从Phaseolus lunatus Linn vel aff的种子中纯化出一种对人类A型血专一的凝集素.该凝集素的粗浸提液都只对A型血细胞凝集,而对B、O型绝不凝集.当纯化的凝集素浓度为0.98μg/mL时,即能凝集A型血细胞,GalNAc、对硝基苯酚-β-D-吡喃半乳糖苷能抑制其凝集作用;酚—硫酸法测得凝集素含有3.8％的中性糖;该凝集素是一个促有丝分裂原,其细胞转化为67.9％;它的分子量为56500,有两种亚基,分子量分别为17200和14600.凝集素分子中亮氨酸和缬氨酸含量较高,分别为9.83和9.64,而酸性氨基酸含量远比碱性氨基酸为高.

AN ANTI-A LECTIN IN THE SEEDS OF PHASEOLUS LUNATUS LINN vel off

An anti-A lectin (called PLA) was purified from seeds of phascolus lunatus by affinity chromato-graphy on hog gastric muein-Scpharose 4B, followed by gel filtration on Sephadex G-200 column. The purified lectin gaive one band on polyacrylamide gel electrophoresis. On SDS-PAGE, the PLA yielded two bands, corresponding to subunits of molecular weight 17200 and 14600. At the pH7.0, it showed an apparent molecular weight of 56500 by gel filtration.The purified lectin contains about 3.8% neutral sugar. This lectin can specifically agglutinate human A and AB erythrocyte at a concentration of 0.98ug/mL and 1.95ug/mL respectively, but doesn't agglutinate B, O or rabbit cells. The anti-A activity of this lectin can be inhibited by N-acetylgalactosamine and O-Nitrophenyl-B-D-galacto-pyranoside. This lectin is a mitogen, it has mitogenic activity on human peripheral blood lympocytes. Amino acid analyses shows that the lectin contains a large ratio of Leucine, Valine, Aspartic acid and Glutamic acid, and only a small ratio of Lysine, Histidine and Arginine.