title: Cross-linking of proteins by Maillard processes--model reactions of D-glucose or methylglyoxal with butylamine and guanidine derivatives.
abstract: Advanced Maillard reaction in proteins leads to formation of covalently cross-linked aggregates the chemical nature of which is largely unknown. From model reactions of methylglyoxal and butylamine with creatine or alpha-N-acetyl-L-arginine, one main product each was isolated. These two compounds were identified, on the basis of unequivocal spectroscopic evidence, as 2-[(5-butylimino-4-methyl-4,5-dihydro-1H-2-imidazolyl)(methyl)amin o]acetic acid and 2-acetylamino-5-[(5-butylimino-4-methyl-4,5-dihydro-1H-2-imidazoly l)amino]pentanoic acid, respectively. Using D-glucose instead of methylglyoxal, two main products each were obtained from reaction with the respective guanidine derivative. The spectroscopic data definitively establish the formation of the diastereoisomeric 2-[(4-butyl-6,7-dihydroxy-4,5,6,7,8,8a-hexahydroimidazo[4,5-b]a zepin-2-yl)(methyl)amino]acetic acid from the reaction with creatine, and of the diastereoisomeric 2-acetylamino-5-[(4-butyl-6,7-dihydroxy-4,5,6,7,8,8a-hexahydroimidazo [4,5-b]azepin-2-yl)amino]pentanoic acid from the reaction with alpha-N-acetyl-L-arginine. All products were isolated in fairly good yield and represent 1:1:1 adducts of the respective reaction partners. Formation of these compounds thus constitutes an efficient reaction pathway for linking primary amines to guanidine derivatives. It seems justified, therefore, to expect cross-linking of proteins by action of reducing carbohydrates to proceed analogously.
authors.affiliation: Institut für Lebensmittelchemie, Universität Hohenheim, Stuttgart, Germany. ledererm@uni-hohenheim.de
authors.forename: M O
authors.initials: MO
authors.lastname: Lederer
authors.forename: F
authors.initials: F
authors.lastname: Gerum
authors.forename: T
authors.initials: T
authors.lastname: Severin
mesh_terms: D002082:Butylamines / Q000737:chemistry*; D003432:Cross-Linking Reagents / Q000737:chemistry*; D005947:Glucose / Q000737:chemistry*; D006146:Guanidines / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D015416:Maillard Reaction; D011506:Proteins / Q000737:chemistry*; D011765:Pyruvaldehyde / Q000737:chemistry*
chemical_list: D002082:Butylamines; D003432:Cross-Linking Reagents; D006146:Guanidines; D011506:Proteins; D011765:Pyruvaldehyde; D005947:Glucose