A novel synthetic approach to tyrosine dimers based on pterin photosensitization

Oxidative damage to proteins leads to a variety of modifications that are markers of pathogenesis. One of the most important modifications is the dityrosine (Tyr₂ ) cross-link, resulting from an oxidative covalent bond between two tyrosines (Tyr). An optimized methodology for preparation of pure Tyr...

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Autores principales: Reid, Lara Olivia, Castaño, Carolina, Dántola, María Laura, Lhiaubet-Vallet, Virginie, Miranda, Miguel A., Marin, M. Luisa, Thomas, Andrés Héctor
Formato: Articulo Preprint
Lenguaje:Inglés
Publicado: 2017
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Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/128209
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Sumario:Oxidative damage to proteins leads to a variety of modifications that are markers of pathogenesis. One of the most important modifications is the dityrosine (Tyr₂ ) cross-link, resulting from an oxidative covalent bond between two tyrosines (Tyr). An optimized methodology for preparation of pure Tyr₂ is important to investigate in detail its physicochemical properties and reactivity. Pterin (Ptr), the parent and unsubstituted compound of oxidized pterins, is able to photosensitize the cross-linking of free tyrosine (Tyr) and tyrosine residues of peptides and proteins through a photoinduced electron transfer mechanism. We have optimized a simple, one-step photocatalyzed formation of Tyr₂ , using Ptr as photocatalyst. Our procedure is carried out in aqueous solutions under UV-A radiation for few minutes. The purification of Tyr₂ is performed by reverse-phase chromatography. The obtained highly pure solution is used to fully characterize the Tyr₂ (exact mass and ¹H, ¹H- ¹H COSY; DEPT; HSQC and HMBC NMR experiments) and to deeper study its fluorescence properties.