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 e dible crab Scylla underbar serrata underbar by affinity chromatography on D-GalNAc-Separon column. The purified lectin, scyllin, was homogen eous by PAGE and had molecular weight 4800-5000 determined by gel filt ration on Sephadex G-75 and a monomer as determined by SDS-PAGE in pre sence 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 mo re efficiently than gram-negative type. The activity of lectin was opt imum at pH 8 and independent of divalent metal ions. Scyllin was not i nhibited 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-substan ce.