Immunoglobulin G glycosylated

Immunoglobulin G Glycosylation and Galactosyltransferase Changes in Rheumatoid Arthritis... 

Figure 2. Immunoglobulin G glycosylation iV-linked to the nitrogen of Asn in the consensus sequence AsnXaaSer/Thr (adapted from an original by F. Routier with thanks).

Endo, T., Wright, A., Morrison, S.L., and Kobata, A. (1995) Glycosylation of the variable region of immunoglobulin G-site specific maturation of the sugar chains. Mol Immunol. 32(13), 931-940. 

This approaeh was suggested and adopted by two groups of researehers (Steel et ah, 2001 Poon and Johnson, 2001). However, one of the problems of this method is due to the presence of a few highly abundant proteins such as albumin, transferrin, and immunoglobulin G (IgG) in the serum proteome profile, which may distort the separation and/or mask the minor proteins present. Thus selective removal of these proteins, especially albumin (representing 30-50% of the total serum protein) is recommended prior to Ifactionation by 2-DE. In many cases, the differences in the protein of interest in the serum protein profile may be due to post-translational modifications, especially glycosylation. In fact, different glycosylated forms of AFP were detected in the sera of HCC patients (Johnson et ah, 1999). 

To investigate potential mechanisms controlling protein glycosylation we have studied the inter-relationship between lymphocytic GTase activity and serum aga-lactosylated immunoglobulin G levels, GO in healthy individuals and patients with RA and non-autoimmune arthritis [42]. In RA there was reduced GTase activity (Figure 9) and increased GO. A positive linear correlation between B and T cell... 

Type G immunoglobulins (igC) are quantitatively the most important antibodies in the blood, where they form the fraction of y-glob-ulins (see p. 276). IgGs (mass 150 kDa) are tetramers with two heavy chains (H chains red or orange) and two light chains (L chains yellow). Both H chains are glycosylated (violet see also p. 43). 

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