Structure of the oligosaccharide of human J chain

The complete structure of the oligosaccharide moiety of J chain isolated from a Waldenstrom macroglobulin Wa has been established. The oligosaccharide is present in three forms differing in the amount of sialic acid and designated J-A, J-B, and J-C. Removal of the oligosaccharide moiety with glycosidases results in an increased mobility of J chain in sodium dodecyl sulfate polyacrylamide gel electrophoresis corresponding to a shift in apparent molecular weight from 23,500 to 19,500. The preparation and utilization of iodinated glycopeptides for sequence analysis is presented.