title: Model studies on the degradation of phenylalanine initiated by lipid hydroperoxides and their secondary and tertiary oxidation products.
abstract: The reaction of methyl 13-hydroperoxyoctadeca-9,11-dienoate (MeLOOH), methyl 13-hydroperoxyoctadeca-9,11,15-trienoate (MeLnOOH), methyl 13-hydroxyoctadeca-9,11-dienoate (MeLOH), methyl 13-oxooctadeca-9,11-dienoate (MeLCO), methyl 9,10-epoxy-13-hydroxy-11-octadecenoate (MeLEPOH), and methyl 9,10-epoxy-13-oxo-11-octadecenoate (MeLEPCO) with phenylalanine was studied to determine the comparative reactivity of primary, secondary, and tertiary lipid oxidation products in the Strecker degradation of amino acids. All assayed lipids were able to degrade the amino acid to a high extent, although the lipid reactivity decreased slightly in the following order: MeLEPCO > or = MeLCO > MeLEPOH > or = MeLOH > MeLOOH approximately = MeLnOOH. These data confirmed the ability of many lipid oxidation products to degrade amino acids by a Strecker-type mechanism and suggested that, once the lipid oxidation is produced, a significant Strecker degradation of surrounding amino acids should be expected. The contribution of different competitive mechanisms to this degradation is proposed, among which the conversion of the different lipid oxidation products assayed into the most reactive MeLEPCO and the fractionation of long-chain primary and secondary lipid oxidation products into short-chain aldehydes are likely to play a major role.
authors.affiliation: Instituto de la Grasa, Consejo Superior de Investigaciones Científicas, Avenida Padre García Tejero 4, 41012 Seville, Spain.
authors.forename: Rosario
authors.initials: R
authors.lastname: Zamora
authors.forename: Emerenciana
authors.initials: E
authors.lastname: Gallardo
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Hidalgo
mesh_terms: D000079:Acetaldehyde / Q000031:analogs & derivatives / Q000737:chemistry; D015227:Lipid Peroxidation; D008054:Lipid Peroxides / Q000737:chemistry*; D015416:Maillard Reaction; D010084:Oxidation-Reduction; D010649:Phenylalanine / Q000737:chemistry*
chemical_list: D008054:Lipid Peroxides; D010649:Phenylalanine; D000079:Acetaldehyde; C013192:phenylacetaldehyde