A LOW-MOLECULAR-WEIGHT LECTIN FROM THE EDIBLE CRAB SCYLLA-SERRATA HEMOLYMPH - PURIFICATION AND PARTIAL CHARACTERIZATION

A low-molecular weight lectin was isolated from the hemolymph of the edible crab Scylla underbar serrata underbar by affinity chromatography on D-GalNAc-Separon column. The purified lectin, scyllin, was homogeneous by PAGE and had molecular weight 4800-5000 determined by gel filtration on Sephadex G-75 and a monomer as determined by SDS-PAGE in presence of 2-mercaptoethanol. Scyllin agglutinated human type O, A and B erythrocytes almost to the same degree as well as those from rabbit, rat, hamster and guinea pig. It agglutinated gram-positive bacteria more efficiently than gram-negative type. The activity of lectin was optimum at pH 8 and independent of divalent metal ions. Scyllin was not inhibited by simple sugars. It was inhibited strongly by fetuin, human glycophorin and ceruloplasmin, and moderately by porcine stomach mucin, birds' nest glycoprotein, antithrombin III and blood group O-substance.