title: Formation of alpha-aminoadipic and gamma-glutamic semialdehydes in proteins by the maillard reaction.
abstract: Recent research has demonstrated that nonenzymatic glycation (the Maillard reaction) lead to the formation of carbonyl groups and advanced glycation end products (AGEs) in proteins. Such oxidative modifications are a major contributing factor to diabetic complications and aging. alpha-Aminoadipic semialdehyde (AAS) and gamma-glutamic semialdehyde (GGS) have been identified as the major carbonyl products in oxidized proteins both in vitro and in vivo. AAS is an oxidative deamination product of lysine residue, while GGS originates from arginine and proline residues. To evaluate oxidative damage to proteins by the Maillard reaction, we developed a method of detecting AAS and GGS by high-performance liquid chromatography (HPLC). The aldehydic residues in proteins were derivatized by reductive amination with NaCNBH3 and p-aminobenzoic acid (ABA), a fluorescence regent. After acid hydrolysis of the ABA-derivatized protein, ABA-AAS and ABA-GGS were measured by fluorometric HPLC. Thus, AAS and GGS could be detected in various proteins such as human plasma protein using the present method. Accumulation of both aldehydic residues was observed in oxidized proteins by reactive oxygen species. Furthermore, AAS and GGS were markedly formed in the incubation of BSA with ascorbic acid. The formation of both aldehydic residues was also observed in the incubation of BSA with 100 mM glucose or 1.0 mM methylglyoxal in the absence and presence of 100 microM Fe3+ for 2 weeks. These results suggest that the Maillard reaction can contribute to the formation of AAS and GGS in vivo.
authors.affiliation: Division of Bioscience and Biotechnology for Future Bioindustries, Graduate School of Agricultural Science, Tohoku University, Sendai, 981-8555, Japan.
authors.forename: Mitsugu
authors.initials: M
authors.lastname: Akagawa
authors.forename: Daisuke
authors.initials: D
authors.lastname: Sasaki
authors.forename: Yayoi
authors.initials: Y
authors.lastname: Kurota
authors.forename: Kyozo
authors.initials: K
authors.lastname: Suyama
mesh_terms: D015074:2-Aminoadipic Acid / Q000031:analogs & derivatives* / Q000032:analysis; D000578:Amidines / Q000032:analysis; D002273:Carcinogens / Q000032:analysis; D005971:Glutamates / Q000032:analysis*; D017127:Glycation End Products, Advanced / Q000032:analysis; D006801:Humans; D015416:Maillard Reaction; D009153:Mutagens / Q000032:analysis; D011506:Proteins / Q000737:chemistry*; D012709:Serum Albumin / Q000737:chemistry; D012710:Serum Albumin, Bovine / Q000737:chemistry
chemical_list: D000578:Amidines; D002273:Carcinogens; D005971:Glutamates; D017127:Glycation End Products, Advanced; D009153:Mutagens; D011506:Proteins; D012709:Serum Albumin; D015074:2-Aminoadipic Acid; D012710:Serum Albumin, Bovine; C000061:allysine; C021199:glutamic acid gamma-semialdehyde; C046728:2,2'-azobis(2-amidinopropane)