Purification and properties of the hemagglutinin from Maclura pomifera seeds

Maclura promifera seeds contain a protein which agglutinates human erythrocytes at concentrations as low as 4 ng/mL. This property is related to its ability to bind with high specificity various alpha-D-galactopyranosides. The agglutinin, which was pruified by affinity adsorption, exhibits one band on immunoelectrophoresis and displays one peak during ultracentrifugation, isoelectric focusing, and gel permeation chromatography. The active protein has a molecular weight of 40 000-43 000 and contains two dissimilar polypeptide chains of 12 000 and 10 000, respectively.