Fig. 1
Alternative in vivo AGE generation routes. Reducing sugars, such as glucose, fructose, and glyceraldehyde, react non-enzymatically with the amino groups of proteins to form reversible Schiff bases and Amadori products/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 AGEs. HbA1c: hemoglobin A1c; CML: Nε-(carboxymethyl)lysine; GO-AGEs: glyoxal-derived AGEs; Glycol-AGEs: glycolaldehyde-derived AGEs; Glu-AGEs: glucose-derived AGEs; 3-DG-AGEs: 3-deoxyglucosone-derived AGEs; MGO-AGEs: methylglyoxal-derived AGEs; Glycer-AGEs: glyceraldehyde-derived AGEs; TAGE: toxic AGEs; Fru-AGEs: fructose-derived AGEs; AR: aldose reductase; SDH: sorbitol dehydrogenase; FK: fructokinase; P-NH2: free amino residue of a protein