Isolation, purification and characterization of three lectins from ant eggs (Oecophylla smaragdina fabr.)

Three lectins have been isolated from an extract of ant egg and purified by gel filtration on Sephadex G-75 of the 100% ammonium sulfate fraction from the crude extract, followed by ion-exchange chromatography on DEAE-cellulose. All the lectins were homogeneous as judged by polyacrylamide gel electrophoresis. The molecular weights of the lectins, AEL-I, AEL-II, and AEL-III, as estimated by gel filtration, were 195,000, 105,500, and 84,000. All the lectins were found to be composed of four sub-units of unequal sizes, and are glycoproteins with a neutral sugar content of 3.0–7.5%. The lectins agglutinated rat red blood-cells; in a hapten-inhibition study, D-galactose was found to be a better inhibitor for AEL-I and AEL-II whereas D-mannose was a better inhibitor for AEL-III.