LC-electrospray ionization-MS analysis of the glycosylation pattern of the glycoengineered cetuximab (9). The deconvoluted spectra of the heavy chain and the fragments are shown. (A) Full-length heavy chain (HC). (B) Fc fragment. (C) Fd fragment. (D) Light chain (LC). Fuc, fucose; Gal, galactose; GlcNAc, N-acetylglucosamine; Man, mannose; NeuAc, N-acetylneuraminic acid.