Ulex europaeus agglutinin (UEA I) is isolated from gorse seeds. It has a molecular weight of 63 kDa that consists of two subunits and has an isoelectric point between pH 4.5 and pH 5.1. The lectin is a glycoprotein that has no mitogenic activity and agglutinates type O erythrocytes, and of a lesser degree to individuals with A2 erythrocytes.

UEA I has a carbohydrate specificity for L-fucose and elutes with the sugar L-fucose. The lectin reacts strongly with alpha(1,2) linked fucose residues but poorly or not at all with alpha(1,3) or alpha(1,6)-linked fucose. UEA I is unable to bind internal fucose structures and the presence of an internal alpha(1,3)-linked fucose on the H type 2 oligosaccharide decreases lectin affinity for this blood group antigen by 3-fold.

UEA I has been used as a marker for vascular endothelium and used to identify endothelial cells of benign vascular lesions more specifically than antibodies of Factor VII-related antigen. UEA I coated magnetic beads have been used to isolate endothelial cells associated with micro-vessels for subsequent cell culture. This lectin has also been used to differentiate between angiosarcomas and epithelial tumors.