Figure 3.

(A) Reverse phase-HPLC analysis of the products formed by ligation between the oligosaccharide, NA2FB, and the aminooxyacetyl peptide. Peak 1, glycopeptide; peaks 2 and 3, side products formed between the aminooxyacetyl peptide with formaldehyde and acetone, respectively. Identities of the peaks were confirmed by mass spectrometric analysis of the HPLC fractions. The HPLC conditions are described in Materials and Methods. (B) Mass spectrometric measurement of an aliquot of the crude ligation reaction products were analyzed without further purification. Peaks 1–3 in the mass spectrum correspond to fractions 1–3 in A. Peak 4 is a fragment ion produced through cleavage of the oxime N-O bond during the MALDI-MS process. Peak 5 was not identified. Yields of the ligation reaction were calculated from the areas of the HPLC peaks.