Alpha-1-proteinase inhibitor (API) is one of the acute phase proteins. Following an inflammatory stimuli the concentration of API increased up to four folds. Accompanying these quantitative changes, there is qualitative alterations in the structure of carbohydrate moiety (glycosylation). To determine the alterations in the glycosylation of API in inflammation, API was isolated from the sera of healthy individuals and from patients with rheumatoid arthritis and Crohn’s disease. The isolated proteins were hydrolyzed to release the monosaccharides. Monosaccharide analysis of isolated API was carried out using high-performance anion-exchange chromatography with pulsed amperometric detection system (HPAE/PAD). Using a lectin binding assay (LBA) which was reported recently, the glycosylation of API was further studied. The results of monosaccharide analysis and LBA showed that in inflammation the fucose content of API is increased. Observation from both methods indicated the increase branching of API in inflammation. These findings may help to develop more precise markers for monitoring pathological progression in these diseases.

Keywords: Alpha-1-proteinase inhibitor, Crohn’s disease, glycosylation, inflammation rheumatoid arthritis

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