title: Oxidation of peptidyl 3,4-dihydroxyphenylalanine analogues: implications for the biosynthesis of tunichromes and related oligopeptides.
abstract: The o-diphenolic amino acid L-3,4-dihydroxyphenylalanine (dopa), the enamine alpha,beta-dehydro-3,4-dihydroxyphenylalanine (delta-dopa), and/or hydroxylated derivatives thereof, are integrated into the primary sequence of many scleroproteins and polyphenolic oligopeptides such as the celenamides, tunichromes, and halocyamines. After oxidation of N-acetyldopa ethyl ester, a low mol wt analogue of peptidyl dopa, the resultant o-quinone tautomerized to (Z)-alpha,beta-dehydro-3,4-dihydroxyphenylalanine ethyl ester. We have characterized this delta-dopa derivative and an acetate 1,4-addition product formed during the synthesis. Tautomerization of peptidyl dopa quinone to delta-dopa may be involved in the biosynthesis of delta-dopa-containing oligopeptides.
authors.affiliation: Department of Chemistry, University of California, Davis 95616.
authors.forename: S W
authors.initials: SW
authors.lastname: Taylor
authors.forename: T F
authors.initials: TF
authors.lastname: Molinski
authors.forename: L M
authors.initials: LM
authors.lastname: Rzepecki
authors.forename: J H
authors.initials: JH
authors.lastname: Waite
mesh_terms: D004295:Dihydroxyphenylalanine / Q000031:analogs & derivatives* / Q000737:chemistry; D015394:Molecular Structure; D009842:Oligopeptides / Q000096:biosynthesis* / Q000737:chemistry*; D009930:Organic Chemicals; D010084:Oxidation-Reduction; D010860:Pigments, Biological / Q000096:biosynthesis* / Q000737:chemistry
chemical_list: D009842:Oligopeptides; D009930:Organic Chemicals; D010860:Pigments, Biological; D004295:Dihydroxyphenylalanine; C021765:tunichrome