Glycosylation Test Peptides

Discovery
The glycosylation test peptide, Bz-Asn-Gly-Thr-NH2 was first used by Angela Dieckmann-Schuppert et al., to elucidate the mode and extent of protein glycosylation in P. falciparum1.

Structural characteristics
Commercially available glycosylation test peptides:
Bz-Asn-Gly-Thr-NH2 ( Mr: 393.40)
Dnp-Arg-Asn-Ala-Thr-Ala-Val-NH2 (Mr: 795.81)
These peptides contain the consensus sequence Asn-X-Thr, known as a potential asparagine glycosylation site2.

Mode of action
Sugars destined to be utilized in protein glycosylation must first be activated by conversion to their nucleotide derivatives prior to eventually being attached to dolichol-(pyro)phosphate or to being directly incorporated into glycans. Oligosaccharyl-transferase activity is then determined by incubating DolPP-oligosaccharide and peptide (N -benzoyl-Asn-Gly-Thr-NH2) in the presence of enzyme and reagents. The test peptide undergoes glycosylation and the nature of the (O- or N-) glycosylation reaction is analysed based on the glycosylated product1.

Functions
Bz-Asn-Gly-Thr-NH2 is used to study the N-glycosylation activity of cell lysates. Dnp-Arg-Asn-Ala-Thr-Ala-Val-NH2 has been used to probe the N-glycosylation activity of cell lysates of Trypanosoma gondii and Trypanosoma brucei brucei2.

References
1.Dieckmann-Schuppert A, Bender S, Odenthal-Schnittler M, Bause E, Schwarz RT (1992). Apparent lack of N-glycosylation in the asexual intraerythrocytic stage of Plasmodium falciparum. Eur. J. Biochem. 205(2):815-825.
2.Dieckmann-Schuppert A, Bause E, Schwarz RT (1994). Glycosylation reactions in Plasmodium falciparum, Toxoplasma gondii, and Trypanosoma brucei brucei probed by the use of synthetic peptides. Biochim Biophys Acta. 1199(1):37-44.