Table II. IgA1 HR fragments analyzed by ECD/ETD fragmentation.

§ The residues in red are sites of O-glycan attachment. The underlined residues are the likely basic sites of proton attachment.

* Proteolytically generated fragments previously analyzed from other myeloma proteins (20, 22).

^† ECD MS/MS spectra of the IgA1 HR N-terminal peptides are provided in supplemental Fig. 4.