Patent ID: 9410966
Filing Date: 2016-08-09
CPC Classification: G01N

Claim Text:
1. A method for identifying a site of N-glycosylation on a protein, the method comprising: incubating a eukaryotic cell with an isotopic labeling composition comprising two or more different isotopic labels to obtain an isotopically labeled sample of N-glycosylated proteins; enzymatically producing peptides from the isotopically labeled sample of N-glycosylated proteins to obtain an enzymatically treated sample of isotopically labeled peptides; subjecting the enzymatically treated sample of isotopically labeled peptides to liquid-chromatography-tandem mass spectrometry; identifying a predetermined isotopic pattern of the enzymatically treated, isotopically labeled sample of peptides in a mass spectrum at one or more retention times; determining an amino acid sequence of an isotopically labeled peptide present at the one or more retention times; and identifying the site of N-glycosylation on the isotopically labeled protein based on the determined amino acid sequence.