Abnormal circulating enzyme concentration or activity Reduced circulating alpha-1,3-fucosyltransferase activity 2024-03-09T17:10:09Z Concentration or activity of alpha-1,3-fucosyltransferase is below the lower limit of normal in the blood circulation. The alpha 3 fucosyltransferases are a family of glycosyltransferases involved in the addition of fucose onto glycoproteins and glycolipids. One of the best defined roles for the alpha 3 fucosyltransferases is in the biosynthesis of the carbohydrate antigen sialyl Lewis X, the minimal ligand for the selectin family of adhesion molecules.