Physicochemical studies on glycation‐induced structural changes in human IgG

Abstract

Glycation of biomolecules leads to the formation of advanced glycation end products (AGEs). Glycation of immunoglobulin G (IgG) has been implicated in autoimmune diseases such as rheumatoid arthritis (RA). In this study, human IgG was glycated with physiological concentration of glucose. The changes induced in IgG were analyzed by UV, fluorescence, circular dichroism, and Fourier transform infrared (FTIR) spectroscopy; thermal denaturation studies, native, and Sodium dodecyl sulphate (SDS)‐polyacrylamide gel electrophoresis. The ketoamine moieties and carbonyl content were also quantitated in glycated IgG. We report structural perturbations, increased carbonyl content, and ketoamine moieties in the glycated IgG. This may interfere with the normal function of IgG and may contribute to initiation of arthritic complications. AGEs damaged IgG may be used as a biomarker for early detection of RA and the associated secondary complications. © 2012 IUBMB Life, 2012

Immunological studies on glycated human IgG

“…Increasing concentrations of anti-AGE-IgG antibodies were incubated with a constant amount of antigen. Our previous study revealed fragmentation in AGE-IgG in SDS-PAGE (Ahmad et al, 2012). The same is visible here when antigen alone was electrophoresed (lane 1 ; Fig.…”

“…In our previous study, we have shown that in vitro treatment of human IgG with glucose causes structural alterations in IgG (Ahmad et al, 2012). The glycation induced alterations in IgG were examined by UV spectroscopy which showed hyperchromicity at 278 nm as compared to native IgG, which may be attributed to the exposure of chromophoric aromatic amino acid residues due to the unfolding and fragmentation of protein as a result of glycation (Jairajpuri et al, 2007).…”

“…Our previous study (Ahmad et al, 2012) has shown structural perturbation in human IgG upon glycation. Native IgG showed an absorbance peak at 278 nm.…”

Preferential recognition of epitopes on AGE–IgG by the autoantibodies in rheumatoid arthritis patients

“…The inhibitors were native IgG and AGE-IgG. iological concentration of glucose for 20 days exhibited extensive damage analyzed by various physicochemical techniques [19]. AGE-IgG was found to be a potent antigenic stimulus inducing high titre antibodies in rabbits as compared to native IgG [20].…”

Dietary Polyamines and Diseases: Reducing Polyamine Intake Can Be Beneficial In Cancer Treatment

“…Spermine and spermidine have been shown to display a significant antiglycation effect at physiological concentration suggesting the role for polyamines in diabetes [67]. Many of the secondary complications of diabetes result from protein glycation and oxidation mediated by agents and processes against which carnosine may protect [68,69]. Additionally there are a number of observations which suggest an inverse relationship between diabetes and carnosine.…”