title: Formation mechanisms of melanoidins and fluorescent pyridinium compounds as advanced glycation end products.
abstract: The formation mechanisms of melanoidins as advanced glycation end products (AGEs) have not been resolved. Blue and red pigments generated in the D-xylose-glycine reaction system are postulated to be intermediate oligomers in the generation of melanoidins. A novel blue pigment, designated blue-M5, was identified as a similar structure to blue-M1 except for the side chain of two dihydroxypropyl groups. Blue pigments were also generated in the D-glucose-glycine and D-xylose-beta-alanine reaction systems as well as in the D-xylose-glycine reaction system. Blue pigments by the Maillard reaction might be formed by the decarboxylation of two molecules of pyrrolopyrrole-2-carbaldehydes (PPA). PPA, composed of a side chain of a dihydroxypropyl group, was identified as a precursor of blue pigments. In fact, blue-M5 was generated by the incubation of PPA alone. Blue pigments, which involved pyrrolopyrrole structures, were readily changed to brown polymers. Glyceraldehyde-derived pyridinium (GLAP) compound, a glyceraldehyde-derived fluorescent AGE, and lysyl-pyrropyridine, a 3-deoxyglucosone-derived fluorescent AGE, were detected at higher levels in the plasma proteins and the tail tendon collagen of streptozotocin-induced diabetic rats compared to normal rats. GLAP and lysyl-pyrropyridine, therefore, might be related to the progression of diabetic complications.
authors: Department of Agricultural Chemistry, Meiji University, Kanagawa 214-8571, Japan. fumi@isc.meiji.ac.jp
authors: Fumitaka
authors: F
authors: Hayase
authors: Teruyuki
authors: T
authors: Usui
authors: Yoriyuki
authors: Y
authors: Ono
authors: Yoshinobu
authors: Y
authors: Shirahashi
authors: Tomomi
authors: T
authors: Machida
authors: Takashi
authors: T
authors: Ito
authors: Nozomu
authors: N
authors: Nishitani
authors: Kazuhito
authors: K
authors: Shimohira
authors: Hirohito
authors: H
authors: Watanabe
mesh_terms: D000818:Animals; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism; D017127:Glycation End Products, Advanced / Q000737:chemistry / Q000378:metabolism*; D005985:Glyceraldehyde / Q000032:analysis / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D015416:Maillard Reaction; D011108:Polymers / Q000737:chemistry / Q000378:metabolism*; D011726:Pyridinium Compounds / Q000737:chemistry / Q000378:metabolism*; D051381:Rats
chemical_list: D017127:Glycation End Products, Advanced; D011108:Polymers; D011726:Pyridinium Compounds; C011908:melanoidin polymers; D005985:Glyceraldehyde