Purification And Partial Characterization Of Seed Lectins From Robinia Pseudoacacia L.

Many researches on purification and characterization of plant lectins have been reported. But there were very few studies on seed lectins from Robinia pseudoacacia L. in China. This paper reported seed lectins from Robinia pseudoacacia L and made some preliminary studies on partial biology characterizations and inhibition to pathogenic fungi so as to do some priority basis for the next studies.Two seed lectins from Robinia pseudoacacia L.( RPsA I and RPsA II) were purified by extraction, fraction with ammonium sulphate, Seopharose 4B iron-exchange and Sephadex G-150 gel filtration. The purified lectins showed a single band on PAGE, and a single band on SDS-PAGE. The molecular weights of the subunits of RPsA I and RPsA II were 38 000 and 31 000 respectively. Each may consist of the same four subunits.The results showed the lowest concentration of two purified seed lectins agglutinated rabbit red cell were 7.80ug/ml and 15.60ug/ml respectively. The agglutinated reaction could be inhibited by L(+)-Arabi-nose, D-Fructose, D ( + ) -Galactose and Maltose. It was stable to hot reaction and the activity was decreased when the pH was over 9.5 and below 5.It was found that RPsA I can inhibit the hyphal growth of three pathogenic fungi including Dothiorella gregaria Sacc. , Melanconium.oblongum Berk, and Cryphonectria parasitica (Murr.) Barr., espacifily Dothiorella gregaria Sacc. Under the different concentration of RPsA I , the inhibition activities to these fungi were tested. The results showed that the effect of inhibition increased as the augment of liquor indicator, and the inhibiting diameter was also enlarged gradually. In the test for inhibition to hyphae, the abnormal morphology such as hyphae twisting and cytoplasm condensation caused by RPsA I were also observed.