In enzymology, a galactoside 2-alpha-L-fucosyltransferase (EC 2.4.1.69) is an enzyme that catalyzes the chemical reaction

GDP-beta-L-fucose + beta-D-galactosyl-R GDP + alpha-L-fucosyl-1,2-beta-D-galactosyl-R

Thus, the two substrates of this enzyme are GDP-beta-L-fucose and beta-D-galactosyl-R, whereas its two products are GDP and alpha-L-fucosyl-1,2-beta-D-galactosyl-R.

This enzyme belongs to the family of glycosyltransferases, specifically the hexosyltransferases. This enzyme participates in 4 metabolic pathways: glycosphingolipid biosynthesis - lactoseries, glycosphingolipid biosynthesis - neo-lactoseries, glycosphingolipid biosynthesis - globoseries, and glycan structures - biosynthesis 2.

The systematic name of this enzyme class is:

• GDP-beta-L-fucose:beta-D-galactosyl-R 2-alpha-L-fucosyltransferase

Other names in common use include:

• blood group H alpha-2-fucosyltransferase
• guanosine diphosphofucose-galactoside 2-L-fucosyltransferase
• alpha-(1->2)-L-fucosyltransferase
• alpha-2-fucosyltransferase
• alpha-2-L-fucosyltransferase
• blood-group substance H-dependent fucosyltransferase
• guanosine diphosphofucose-glycoprotein 2-alpha-fucosyltransferase
• guanosine diphosphofucose-lactose fucosyltransferase
• GDP fucose-lactose fucosyltransferase
• guanosine diphospho-L-fucose-lactose fucosyltransferase
• guanosine diphosphofucose-beta-D-galactosyl-alpha-2-L-fucosyltransferase
• guanosine diphosphofucose-galactosylacetylglucosaminylgalactosylglucosylceramide
• alpha-L-fucosyltransferase, guanosine diphosphofucose-glycoprotein 2-alpha-L-fucosyltransferase
• H-gene-encoded beta-galactoside alpha1->2fucosyltransferase
• secretor-type beta-galactoside alpha1->2fucosyltransferase
• beta-galactoside alpha1->2fucosyltransferase
• GDP-L-fucose:lactose fucosyltransferase

• Basu S, Basu M, Chien JL (1975). "Enzymatic synthesis of a blood group H-related glycosphingolipid by an alpha-fucosyltransferase from bovine spleen". J. Biol. Chem. 250 (8): 2956–62. doi:10.1016/S0021-9258(19)41579-2. PMID 804484.
• Beyer TA, Hill RL (1980). "Enzymatic properties of the beta-galactoside alpha 1 leads to 2 fucosyltransferase from porcine submaxillary gland". J. Biol. Chem. 255 (11): 5373–9. doi:10.1016/S0021-9258(19)70796-0. PMID 7372640.
• Beyer TA, Sadler JE, Hill RL (1980). "Purification to homogeneity of H blood group beta-galactoside alpha 1 leads to 2 fucosyltransferase from porcine submaxillary gland". J. Biol. Chem. 255 (11): 5364–72. doi:10.1016/S0021-9258(19)70795-9. PMID 6246105.
• Grollman AP (1966). "GDP-l-fucose: Lactose fucosyltransferase from mammary gland". GDP-L-fucose:lactose fucosyltransferase from mammary gland. Methods Enzymol. Vol. 8. pp. 351–353. doi:10.1016/0076-6879(66)08065-0. ISBN 978-0-12-181808-1.