Figure 1.
Alternative routes for the formation of advanced glycation end-products in vivo. Reducing sugars, such as glucose, fructose, and glyceraldehyde are known to react non-enzymatically with the amino groups of proteins to form reversible Schiff bases and Amadori product/Heyns products. These early glycation products undergo further complex reactions such as rearrangement, dehydration, and condensation to become irreversibly cross-linked, heterogeneous fluorescent derivatives, termed advanced glycation end-products (AGEs). Glu-AGEs: Glucose-derived AGEs; Fru-AGEs: Fructose-derived AGEs; Glycer-AGEs: Glyceraldehyde-derived AGEs; Glycol-AGEs: Glycolaldehyde-derived AGEs; MGO-AGEs: Methylglyoxal-derived AGEs; GO-AGEs: Glyoxal-derived AGEs; 3-DG-AGEs: 3-deoxyglucosone-derived AGEs; CML: Nε-(carboxymethyl)lysine; P-NH2: Free amino residue of a protein; AR: Aldose reductase; SDH: Sorbitol dehydrogenase; FK: Fructokinase; HFCS: High-fructose corn syrup; HbA1c: Hemoglobin A1c; TAGE: Toxic advanced glycation end-products.