| Lectins were extracted from 8 species of mollusca, with PBS (pH 7.2) buffer, then with 50%ammonium sulfate precipitation and frozen dry. They were tested for agglutinating activity using 12 kinds of erythrocytes of animals and human,5 species of unicellular algae, and 10 species of unicellular microbes in order to find stronger activity of lectin. The results showed that there were evident difference in different lectins, the agglutinating activity of Neptunea cumingi lectin was the most strongest. The rabbit erythrocytes was the most sensitive cells respectively by synthesizing the agglutination activity of all lectins.Taking Neptunea cumingi as experiment material, with 50%ammonium sulfate saturation, exchange chromatography of the DEAE-Sepharose colum and gel chromatography on the sephacryl S-200-HR colum, a lectin (NCL) was purified from Neptunea cumingi. Further more, the molecular weight, sugar content, isoelectric point, UV absorption spectrum, amino acid composition, carbogydrate-binding specificity, influence of pH, temperature, EDTA, metal cations and salinity to NCL were determined. Meanwhile, NCL were detected the thermal stability and the influence of pH to the internal structure by using intrinsic fluorescence spectroscopy. The intrinsic fluorescence of NCL was not quenched by KI, but was quenched by acrylamide and CsCl, indicating that the Trp residues of NCL were lacated in the hydropyobic pocket of the glycoprotein surface.The lectin of Neptunea cumingi were extracted in diffenret seasons, then compared their agglutinating activity, thermal stability and the influence of pH to the agglutinative activity. The results showed that there was significant difference in lectins from every season, including the stronger activity from the lectin in spring and winter, and the weakest in autumn. The optimum pH was at 6 or 7 and thermal stability maintained a high degree of consistency for the agglutinating activity of NCL from different seasons. |
PDF Full Text Request