info:eu-repo/semantics/article
Photosensitized Dimerization of Tyrosine: The Oxygen Paradox†
Fecha
2022-05Registro en:
Dantola, Maria Laura; Neyra Recky, Jael Rhode; Lorente, Carolina; Thomas, Andrés Héctor; Photosensitized Dimerization of Tyrosine: The Oxygen Paradox†; Wiley Blackwell Publishing, Inc; Photochemistry and Photobiology; 98; 3; 5-2022; 687-695
0031-8655
CONICET Digital
CONICET
Autor
Dantola, Maria Laura
Neyra Recky, Jael Rhode
Lorente, Carolina
Thomas, Andrés Héctor
Resumen
In electron-transfer initiated photosensitization processes, molecular oxygen (O2) is not involved in the first bimolecular event, but almost always participates in subsequent steps giving rise to oxygenated products. An exception to this general behavior is the photosensitized dimerization of tyrosine (Tyr), where O2 does not participate as a reactant in any step of the pathway yielding Tyr dimers (Tyr2). In the pterin (Ptr) photosensitized oxidation of Tyr, O2 does not directly participate in the formation of Tyr2 and quenches the triplet excited state of Ptr, the reactive species that initiates the process. However, O2 is necessary for the dimerization, phenomenon that we have named as the oxygen paradox. Here, we review the literature on the photosensitized formation of Tyr2 and present results of steady-state and time resolved experiments, in search of a mechanistic model to explain the contradictory role of O2 in this photochemical reaction system.