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