Five structurally related proteins from affinity-purified Maclura pomifera lectin

Affinity-purified Maclura pomifera lectin (MPL) elutes from a gel filtration column as a single symmetrical peak with characteristics expected for a single protein of approximately 40 000 daltons. This material can be dissociated into two dissimilar polypeptide chains of approximately 10 000 daltons. Ion-exchange chromatography on DEAE-cellulose resolves affinity-purified MPL into five components. These proteins are structurally related and contain varying proportions of the two polypeptide chains. Two of these tetrameric lectins, each composed solely of one of these chains, display differences in mobility during discontinuous polyacrylamide gel electrophoresis and ion-exchange chromatography, but display no detectable differences in hemagglutination of human erythrocytes and interactions with carbohydrates.