title: Isolation and characterization of glyoxal-arginine modifications.
abstract: 5-(4,5-Dihydroxy-2-imino-1-imidazolidinyl)norvaline (1) was identified as the only product of the early reaction of arginine with glyoxal, which was slowly degraded to N(5)-[[(carboxymethyl)amino](imino)methyl]ornithine (3, N(7)-carboxymethylarginine). No other structures could be detected within a range of pH 4-8 and 20-50 degrees C in reaction conditions. The rates of formation for both products increased with pH and temperature. In equilibrium, the vincinal diol groups of 1 were 86% trans configured. The formation of 1 was reversible, as could be shown by cis-trans isomerization of the separated isomers and by regeneration of arginine in the presence of the alpha-dicarbonyl trapping reagents, o-phenylenediamine and aminoguanidine. Both 1 and 3 were converted to 5-(2-imino-5-oxo-1-imidazolidinyl)norvaline (2) only under strong acidic conditions.
authors: Institute of Food Chemistry, Technical University of Berlin, Gustav-Meyer-Allee 25, TIB4/3-1, 13355 Berlin, Germany. marcus.glomb@tu-berlin.de
authors: M A
authors: MA
authors: Glomb
authors: G
authors: G
authors: Lang
mesh_terms: D001120:Arginine / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D008401:Gas Chromatography-Mass Spectrometry; D006037:Glyoxal / Q000737:chemistry*; D007093:Imidazoles / Q000737:chemistry*; D007700:Kinetics; D015394:Molecular Structure; D014633:Valine / Q000031:analogs & derivatives / Q000737:chemistry*
chemical_list: C428946:5-(4,5-Dihydroxy-2-imino-1-imidazolidinyl)norvaline; D007093:Imidazoles; D006037:Glyoxal; D001120:Arginine; D014633:Valine