N-Acetylglucosaminyltransferase V (MGAT4B) is the enzyme that catalyzes the formation of the β1,6-GlcNAc branch of N-glycans in the Golgi apparatus using UDP-GlcNAc as the donor substrate. N-Acetylglucosaminyltransferase V is involved in cancer malignancy and autoimmune disease etiology.