title: The peroxidase-catalyzed oxidation of enkephalins.
abstract: In vitro experiments are reported showing that Leu-enkephalin and Metenkephalin, in the presence of hydrogen peroxide, can be oxidized by horseradish peroxidase. The products formed are strongly fluorescent and characterized by absorption peaks with maxima at 290 nm and 315 nm. The effects of substrate and enzyme concentrations on the oxidation rate of enkephalins are described. Amino acid analysis of the hydrolysates from peroxidase-treated enkephalins provides evidence for the presence of dityrosine. The data suggest that the oxidation leads to the production of enkephalin dimers with a linkage between the N-terminal tyrosine residues. Data are also obtained indicating that enkephalins function as hydrogen donors for mammalian peroxidases.
authors.affiliation: Dipartimento di Scienze Biochimiche, Università La Sapienza Rome, Italy.
authors.forename: M A
authors.initials: MA
authors.lastname: Rosei
authors.forename: C
authors.initials: C
authors.lastname: Blarzino
authors.forename: C
authors.initials: C
authors.lastname: Foppoli
authors.forename: R
authors.initials: R
authors.lastname: Coccia
authors.forename: C
authors.initials: C
authors.lastname: De Marco
mesh_terms: D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D004743:Enkephalin, Leucine / Q000378:metabolism*; D004744:Enkephalin, Methionine / Q000378:metabolism*; D006735:Horseradish Peroxidase / Q000378:metabolism; D007700:Kinetics; D007784:Lactoperoxidase / Q000378:metabolism; D010084:Oxidation-Reduction; D009195:Peroxidase / Q000378:metabolism; D010544:Peroxidases / Q000378:metabolism*; D013056:Spectrophotometry, Ultraviolet; D014443:Tyrosine / Q000031:analogs & derivatives / Q000032:analysis
chemical_list: D014443:Tyrosine; D004744:Enkephalin, Methionine; D004743:Enkephalin, Leucine; C007543:dityrosine; D006735:Horseradish Peroxidase; D007784:Lactoperoxidase; D010544:Peroxidases; D009195:Peroxidase