Peptide glycosylation is a covalent modification that can potentially improve the physicochemical properties of peptides. Some advantages of glycosylated peptides include: (1) increased bioavailability, (2) increased metabolic stability, (2) targeting specific tissues and organs, (3) reduction in clearance rates, (4) enhanced receptor binding, (5) facilitation of active transport across cell membranes (glucose transporters), and (6) maintaining the overall physical properties of peptides (precipitation, aggregation, thermal and kinetic denaturation).
Glycopeptides are recognized as peptides that contain glycans (carbohydrate molecules) and can be generalized classified into three types based on the linkage or bond type between the amino acid and the glycan: (1) C-linked, (2) O-linked, and (3) N-linked. The most common type in eukaryotic cells is N-linked glycopeptides, noted by the C-N bond from the side chain of asparagine (Asn/N) amino acid. O-Type glycopeptides are named after the C-O bond from the side chains of serine (Ser) and threonine (Thr) amino acids. The least common C-linked types are recognized as the bond between a tryptophan residue and the sugar mannose.
Click chemistry provides a relatively easy approach to peptide glycosylation.
Glucitol-Lys(NOTA)-DPhe-Cys-Tyr-DTrp-Lys-Thr-Cys-Thr-OH (disulfide bridge).
F.-H. Guo, Y.-Q. Chen, T. Liu, B.-J. Chen, J. Du. "Preparation and preliminary biological evaluation of n-Gluc-Lys([Al 18F]NOTA)-TOCA." Journal of Nuclear and Radiochemistry, 34(3), 157-165 (2012)
Complex Glycan Moieties
Simple glycans consisting of only a single sugar molecule, namely D-galactose, D-glucose, or D-mannose, can improve the physicochemical properties of many peptides; however, in some cases, more complex glycans composed of polysaccharides may be required. Our technical team can provide site-selective glycosylations of a variety of linear or branched glycan polysaccharides.
N-Linked glycan polysaccharide.
Common mono- and disaccharide glycans
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