Isolation and characterization of the blood group A-specific lectin from Vicia cracca.

We have isolated the blood group A-specific lectin from Vicia cracca by affinity chromatography on immobilized porcine blood group A/H substance. A molecular weight of 100 000 was obtained by gel filtration and analytical ultracentrifugation. The subunit size when determined by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate was 29 000. The lectin contains no half-cystine or methionine. It is a glycoprotein apparently with one oligosaccharide per subunit. The oligosaccharide contains mainly D-mannose and D-glucosamine but no D-galactose or sialic acid.