荆豆(Ulex europaeus L.)凝集素Ⅰ的细胞表面受体研究

从Ulex europaeus L.种子中纯化的荆豆凝集素I(UEH I),不仅专一地凝集人O型血细胞,也能凝集牛精细胞,表明这些细胞表面存在有UEH I的受体.应用经FITC或~(125)I标记的UEH I与牛精细胞结合,研究受体在精细胞表面的分布;Glc、Con A、PHA和Fuc的浓度对~(125)I-UEH I与O型血细胞结合的影响;O型血细胞和牛精细胞与~(125)I-UEH I的饱和实验,获得饱和结合曲线或竞争性结合曲线,得出各自的Scatchard图,分别计算出O型血细胞和牛精细胞表面的UEH I受体的数目。

STUDY OF THE CELL SURFACE RECEPTOR FOR THE ULEX EUROPAEUS LECTIN

The anti-H specific hemagglutinin has been isolated from the seeds of Ulex europaeus L. by saline extraction, sufficient solid (NH4)2SO4 was added to give 0.4 saturation. The precipitate formed was removed by centrifugation, and further purification of this fraction was achieved by chromatography successively on CM-cellulose and Sephadex G 200 gel filtration for two times. The clectrophoretic homogeneity of the purified hemagglutinin (UEH I) was confirmed by disc-electrophoresis on poly-acryamide gel. The molecular weight of the purified lectin has been proved to be 170,000 by the gel filtration.The minimum hemagglutination dose of the purified lectin is 1.25ug/mL against O type erythrocytes, 500ug/mL against A-type, 40ug/mL against B type and 1.25ug/mL against sperm of cattle.Binding of FITC-UEH I to cattle's sperm shows that most of UEH I receptors on cattle's sperm exist in neck. The foreign lectins effect 125l-UEH I binding to its receptors on O erythrocytes, when the concentrations of PHA and C increase from 0. 1mg/mL to 10mg/mL respectively, the relative bindings decrease from 94-74% to 40-26%, but it increases with BSA. The saccharides effect 125I-UEH I binding to its receptors on O erythrocytes. we found that the L-Fuc and D-Xyl shows no observable variation, but the concentration of D Glc increase from 10-5 to 10-4M, the relative binding decrease rapidly to 30%. The bindings of 125I-UEH I to O erythrocytes and catile's sperm are both raturated processes, but their Seatch-ard plots are irregular. The numbers of UEH I receptor site per cell for human's erythrocytes and cattle's sperm were calculated as follows:O erythrocytes: 4.44 X l04mol/per cell Cattle sperm: 3.04X 104mol/per cell The irregular Scatchard plot for cattle sperm indicates that UEH-I receptors on the cattle sperm's surface are very complicated.