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The effects of oxygen free radicals on the carbohydrate moiety of IgG
Author(s) -
Griffiths H.R.,
Lunec J.
Publication year - 1989
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(89)80199-1
Subject(s) - radical , chemistry , superoxide , moiety , residue (chemistry) , galactose , oxygen , carbohydrate , biochemistry , stereochemistry , organic chemistry , enzyme
The CH2‐linked glycoform of rheumatoid IgG is abnormal in having a reduced galactose content. This has been postulated to be a synthetic defect due to a decrease in the level of rheumatoid B cell galactosyltransferase. However, more recent work has indicated that agalactosylation may be common to chronic inflammatory diseases. In this work we have investigated the effect of oxygen free radicals (OFRs), which are generated by activated phagocytic cells at inflammatory sites, on the carbohydrate moiety of IgG. Radiolytically generated peroxy (ROO • ) and hydroxyl radicals (OH • ) but not superoxide anion radicals (O— 2 − ) were found to destroy galactose on IgG. After OH • attack, this was associated with an increase in the availability of N ‐acetylglucosamine, possibly due to its presence as a terminal residue. These results suggest that the agalactosylation associated with chronic inflammation may not only be synthetic in nature, but may also be a consequence of post‐synthetic degradation by OFRs.