Catalyzes the transfer of L-fucose, from a guanosine diphosphate-beta-L-fucose, to the terminal galactose residue of glycoconjugates through an alpha(1,2) linkage leading to H antigen synthesis that is an intermediate substrate in the synthesis of ABO blood group antigens (PubMed:2118655). H antigen is essential for maturation of the glomerular layer of the main olfactory bulb, in cell migration and early cell-cell contacts during tumor associated angiogenesis (PubMed:18205178). Preferentially fucosylates soluble lactose and to a lesser extent fucosylates glycolipids gangliosides GA1 and GM1a (By similarity). a beta-D-galactosyl-(1->4)-N-acetyl-beta-D-glucosaminyl derivative + GDP-beta-L-fucose = an alpha-L-Fuc-(1->2)-beta-D-Gal-(1->4)-beta-D-GlcNAc derivative + GDP + H(+) ganglioside GA1 + GDP-beta-L-fucose = ganglioside Fuc-GA1 + GDP + H(+) a beta-D-Gal-(1->3)-beta-D-GlcNAc-(1->3)-beta-D-Gal-(1->4)-beta-D-Glc-(1<->1')-Cer(d18:1(4E)) + GDP-beta-L-fucose = alpha-L-fucosyl-(1->2)- beta-D-galactosyl-(1->3)-N-acetyl-beta-D-glucosaminyl-(1->3)-beta-D-galactosyl-(1->4)-beta-D-glucosyl-(1<->1')-N-acylsphing-4-enine + GDP + H(+) a neolactoside nLc4Cer(d18:1(4E)) + GDP-beta-L-fucose = a neolactoside IV(2)-alpha-Fuc-nLc4Cer(d18:1(4E)) + GDP + H(+) ganglioside GM1 + GDP-beta-L-fucose = ganglioside Fuc-GM1 + GDP + H(+) beta-D-galactosyl-(1->3)-N-acetyl-D-galactosamine + GDP-beta-L-fucose = alpha-L-fucosyl-(1->2)-beta-D-galactosyl-(1->3)-N-acetyl-D-galactosamine + GDP + H(+) Protein modification; protein glycosylation. Membrane-bound form in trans cisternae of Golgi. Increased by TNF. Genetic variations in FUT1 define the H blood group and are responsible for the Bombay and para-Bombay phenotypes [MIM:616754]. Erythrocytes from individuals with the Bombay and para-Bombay blood group phenotypes are deficient in H antigens. There are two genes (FUT1 and FUT2) which encode galactoside 2-L-fucosyltransferase. They are expressed in a tissue-specific manner with expression restricted to cells of mesodermal or endodermal origin respectively. Belongs to the glycosyltransferase 11 family. Blood group antigen gene mutation database Fucosyltransferase 1