Characterization and analysis of a novel glycoprotein from snake venom using liquid chromatography-electrospray mass spectrometry and Edman degradation

An N-linked glycosylation in a novel C-lectin protein from snake venom was observed by Edman degradation and liquid chromatography-electrospray mass s pectrometry. The peptides obtained by trypsin cleavage were analyzed to con firm the amino acid sequence and Asn5 was found to be the N-glycosylation s ite. The result was further confirmed by N-glycosidase digestion. In additi on, the protein and tryptic peptides with and without, glycan chain were ch aracterized by mass spectrometry according to the mass difference. The glyc opeptide obtained from proteolytic digestion was analyzed and the glycoform s were identified as high-mannose type by tandem MS coupled with alpha-mann osidase digestion. An oxidized Met residue was detected and located in the protein by mass spectrometry.