The glycopeptides of the mouse immunoglobulin A T15

Cleavage of mouse IgA T15 with papain yielded (a) a glycosylated Fab fragment, (b) a non-glycosylated Fc fragment and (c) a glycosylated C-terminal peptide. The cleavage sites at the hinge and at the end of the Cα3 domain were located by sequencing. The two glycopeptides were prepared from the Fab and C-terminal fragments by pronase digestion. The Cα1 glycopeptide at Asn 155 was complex type with α(1–3)galactose terminal groups, and closely resembled the Asn 171 glycopeptide of mouse IgM (Anderson et al. (1985) Arch. Biochem. Biophys. 243, 605–618). In contrast, the C-terminal glycopeptide at Asn 446 was entirely different from the corresponding IgM glycopeptide, being complex rather than high-mannose type.