AbstractNon-enzymatic glycation is a spontaneous and deleterious phenomenon that normally takes place inside human body and causes tissue damage. In the course of glycation reaction between glycating agents and biomolecules, several reactive perilous intermediates and finally heterogeneous group of compounds, advanced glycation end products (AGEs), are generated. Formations of AGEs are accelerated under disease conditions including diabetes and its complications. Endogenous 3-deoxyglucosone (3-DG) is a powerful glycating agent that glycates biomolecules including proteins compromising its structure and functionality. The production of 3-DG is significantly elevated during diabetes leading to vascular damage through glycation reaction. In the present study, human IgG was glycated with 3-DG to examine the AGEs production (Nε-carboxymethyllysine and pentosidine) by probing the degree of side chain modifications, formation of different intermediates and structural alterations induced by 3-DG on IgG. The results point out AGEs formation, intermediates generation (indicating oxidative stress) and structural alteration upon glycation of IgG by 3-DG, which may disturb normal functioning of IgG and compromise immune response in secondary complications of diabetes.