Title : Characterization of a single glycosylated
asparagine site on a
glycopeptide using solid-phase Edman degradation
Abstract :
- The characterization of site-specific glycosylation is traditionally dependent on the availability of suitable proteolytic cleavage sites between each glycosylated residue , so that peptides containing individual glycosylation sites are recovered
- In the case of heavily glycosylated domains such as the O-glycosylated mucins, which have no available protease sites , this approach is not possible
- Here we introduce a new method to gain site-specific com position al data on the oligosaccharides attached to a single amino acid
- Using a model glycopeptide from a mutant human albumin Casebrook , glycosylated PTH- Asn was recovered after sequential solid-phase Edman degradation, subjected to acid hydrolysis and the sugars were identified by high performance anion exchange chromatography with pulsed amperometric detection
- The PTH- Asn (Sac) derivative was further characterized by ionspray mass spectrometry
- Comparison between an endoproteinase Glu-C glycopeptide and a tryptic glycopeptide showed that the oligosaccharide attached to Asn494 was stable after at least 10 cycles of Edman degradation