Isolation and characterization of the lectin from the green marine alga Ulva lactuca L.

A lectin from the green marine alga Ulva lactuca was isolated by a combination of affinity chromatography on porcine stomach mucin-Sepharose 6B and gel filtration on Sephadex G-50. Ulva lactuca lectin agglutinated various animal and human erythrocytes in the following order O>A(1)>B. The haemagglutinating activity was inhibited by L-fucose, fucoidan, porcine stomach mucin and bovine submaxillary gland mucin. The lectin was stable at variations of pH and temperature and divalent cation dependent. The M-r of U. lactuca agglutinin, determined by gel filtration was 8370, while SDS-PAGE gave one single protein band with a M-r of 17120. The lectin was shown to be rich in acidic and hydroxyl amino acids, but low in basic amino acids.