Oxidative tryptophan modification by terpene- and squalene-hydroperoxides and a possible link to cross-reactions in diagnostic tests.
Hydroperoxides can act as specific haptens and oxidatively modify proteins. Terpene hydroperoxides trigger unusually high frequencies of positive skin reactions in human patients if tested at high concentrations. It is unknown whether this is due to specific hapten formation. Here, we show that both terpene hydroperoxides and the endogenous hydroperoxide formed from squalene can oxidatively modify tryptophan. Oxidative modifications of Trp were recently postulated to explain cross-sensitization between unrelated photosensitizers. Current observations may extend this hypothesis: Oxidative events triggered by endogenous hydroperoxides and hydroperoxides/oxidants derived from xenobiotics might lead to a sensitized state detected by patch tests with high concentrations of hydroperoxides.
†Biosciences, Analytical Chemistry and Process Research Chemistry, Givaudan Schweiz AG, Ueberlandstrasse 138, CH-8600 Duebendorf, Switzerland.
Andreas
A
Natsch
†Biosciences, Analytical Chemistry and Process Research Chemistry, Givaudan Schweiz AG, Ueberlandstrasse 138, CH-8600 Duebendorf, Switzerland.
Roger
R
Emter
†Biosciences, Analytical Chemistry and Process Research Chemistry, Givaudan Schweiz AG, Ueberlandstrasse 138, CH-8600 Duebendorf, Switzerland.
Remo P
RP
Badertscher
†Biosciences, Analytical Chemistry and Process Research Chemistry, Givaudan Schweiz AG, Ueberlandstrasse 138, CH-8600 Duebendorf, Switzerland.
Gerhard
G
Brunner
†Biosciences, Analytical Chemistry and Process Research Chemistry, Givaudan Schweiz AG, Ueberlandstrasse 138, CH-8600 Duebendorf, Switzerland.
Thierry
T
Granier
†Biosciences, Analytical Chemistry and Process Research Chemistry, Givaudan Schweiz AG, Ueberlandstrasse 138, CH-8600 Duebendorf, Switzerland.
Susanne
S
Kern
‡RAPS Fragrance Toxicology, Givaudan International SA, 5 Chemin de la Parfumerie, CH-1214 Vernier, Switzerland.
Graham
G
Ellis
D003955:Diagnostic Tests, Routine; D006861:Hydrogen Peroxide / Q000737:chemistry* / Q000494:pharmacology*; D015394:Molecular Structure; D010084:Oxidation-Reduction / Q000187:drug effects; D014364:Tryptophan / Q000378:metabolism*
D014364:Tryptophan; D006861:Hydrogen Peroxide