title: Structure-reactivity relationship of Amadori rearrangement products compared to related ketoses.
abstract: Structure-reactivity relationships of Amadori rearrangement products compared to their related ketoses were derived from multiple NMR spectroscopic techniques. Besides structure elucidation of six Amadori rearrangement products derived from d-glucose and d-galactose with l-alanine, l-phenylalanine and l-proline, especially quantitative (13)C selective saturation transfer NMR spectroscopy was applied to deduce information on isomeric systems. It could be shown exemplarily that the Amadori compound N-(1-deoxy-d-fructos-1-yl)-l-proline exhibits much higher isomerisation rates than d-fructose, which can be explained by C-1 substituent mediated intramolecular catalysis. In combination with a reduced carbonyl activity of Amadori compounds compared to their related ketoses which results in an increased acyclic keto isomer concentration, the results on isomerisation dynamics lead to a highly significant increased reactivity of Amadori compounds. This can be clearly seen, comparing approximated carbohydrate milieu stability time constants (ACuSTiC) which is 1 s for N-(1-deoxy-d-fructos-1-yl)-l-proline and 10 s for d-fructose at pD 4.20 ± 0.05 at 350 K. In addition, first NMR spectroscopic data are provided, which prove that α-pyranose of (amino acid substituted) d-fructose adopts both, (2)C5 and (5)C2 conformation.
authors.affiliation: Department of Food Chemistry and Food Analysis, Berlin Institute of Technology, Gustav-Meyer-Allee 25, TIB 4/3-1, D-13355 Berlin, Germany. Electronic address: martin.kaufmann@tu-berlin.de.
authors.forename: Martin
authors.initials: M
authors.lastname: Kaufmann
authors.affiliation: Department of Food Chemistry and Food Analysis, Berlin Institute of Technology, Gustav-Meyer-Allee 25, TIB 4/3-1, D-13355 Berlin, Germany.
authors.forename: Philipp M
authors.initials: PM
authors.lastname: Meissner
authors.affiliation: Department of Food Chemistry and Food Analysis, Berlin Institute of Technology, Gustav-Meyer-Allee 25, TIB 4/3-1, D-13355 Berlin, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Pelke
authors.affiliation: Department of Chemistry, NMR Facility, Humboldt University of Berlin, Brook-Taylor-Straße 2, D-12489 Berlin, Germany.
authors.forename: Clemens
authors.initials: C
authors.lastname: Mügge
authors.affiliation: Department of Food Chemistry and Food Analysis, Berlin Institute of Technology, Gustav-Meyer-Allee 25, TIB 4/3-1, D-13355 Berlin, Germany.
authors.forename: Lothar W
authors.initials: LW
authors.lastname: Kroh
mesh_terms: D000596:Amino Acids / Q000737:chemistry*; D007536:Isomerism; D007661:Ketoses / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D009005:Monosaccharides / Q000737:chemistry*
chemical_list: D000596:Amino Acids; D007661:Ketoses; D009005:Monosaccharides
keywords: Amadori compound; Dynamic NMR spectroscopy; Isomerisation dynamics; N-(1-deoxy-d-fructos-1-yl)-l-alanine (PubChem CID: 71316979); N-(1-deoxy-d-fructos-1-yl)-l-phenylalanine (PubChem CID: 71316982); N-(1-deoxy-d-fructos-1-yl)-l-proline (PubChem CID: 71316983); Reactivity; Ring inversion; d-Fructose; d-Fructose (PubChem CID: 5984); d-Fructose + l-Proline (PubChem CID: 118797558); d-Tagatose (PubChem CID: 92092)