GDP-fucose protein O-fucosyltransferase 1 also known as peptide-O-fucosyltransferase 1 (O-FucT-1) is an enzyme that in humans is encoded by the POFUT1 gene.

POFUT-1 belongs to the O-Fuc family of proteins all which is involved in the transferring of o-fucose from GDP-β-L-fucose to substrates.

POFUT-1 responsible for adding fucose sugars in O linkage to serine or threonine residues between the second and third conserved cysteines in EGF-like repeats on the Notch protein.

Pre-NOTCH proteins are translated and deposited in to the endoplasmic reticulum and are then first modified by POFUT-1 then by PGLUT-1 then exported the Golgi apparatus.

in the endoplasmic reticulum POFUT-1 utilizes its sub-strait GDP-β-L-fucose as a donor for the five carbon sugar fucose.