of one putative glycosylation site (Asn40) in D40 MOR peptide. To this end, we treated cellular lysates with PNGase F, an enzyme which removes all N-linked glycans. Western blotting of FLAG-MOR using an anti-FLAG antibody showed that MOR N40 and D40 peptides migrated at approximately the same molecular weight (Fig. 5A, lanes 3-6). This indicates the differences in molecular masses observed for N40 and D40 human peptides is due to differential N-linked glycosylation.
