The predominant oligomannose-type glycan structure observed across the protein, with the exception of N234, is Man5GlcNAc2 (Man, mannose; GlcNAc, N-acetylglucosamine), which demonstrates that these sites are largely accessible to α-1,2-mannosidases but are poor substrates for GlcNAcT-I, which is the gateway enzyme in the formation of hybrid- and complex-type glycans in the Golgi apparatus.