Post-translational modifications of immunoglobulin G:: a mouse IgG variant that lacks the entire CH1 domain

In the present study, we characterized the post-translational modifications of a short-chain variant of mouse IgG2a that lacks the entire C(H)1 domain. The short-chain IgG2a and its proteolytic fragments were subjected to electrosplay ionization- and fast atom bombardment-mass spectrometric analyses. It has been demonstrated that approximately 14% of the heavy chain of the short-chain IgG2a is O-glycosylated with a disaccharide of Gal-GalNAc- at Thr220A in the hinge region, while the O-glycosylation does not occur in its parent IgG2a molecule. Two additional modifications have been detected at the C-termini of both the heavy and light chains of the short-chain IgG2a. Biological significance of the post-translational modifications of the short-chain IgG2a variant is briefly discussed. (C) 2000 Elsevier Science Ltd. AU rights reserved.