Generation of Reactive Oxygen Species during the Photolysis of 6-(Hydroxymethyl)pterin in Alkaline Aqueous Solutions

Photochemical studies of the reactivity of 6-(hydroxymethyl)pterin (=2-amino-6-(hydroxymethyl)pteridin-4(1H)-one; HPT) in alkaline aqueous solutions (pH 10.2-10.8) at 350 nm and room temperature were performed. The photochemical reactions were followed by UV/VIS spectrophotometry, thin-layer chromat...

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Autores principales:	Cabrerizo, F.M., Thomas, A.H., Lorente, C., Dántola, M.L., Petroselli, G., Erra-Balsells, R., Capparelli, A.L.
Formato:	JOUR
Materias:	Alkali metals Amino acids Chromatography Methane Oxidation Oxygen Photochemical reactions Photolysis Solutions Spectrophotometry Stoichiometry Thermal effects Photoproducts Biodiversity 6 hydroxymethylpterin alkali hydrogen peroxide oxygen pterin 6 aldehyde pterin derivative reactive oxygen metabolite singlet oxygen unclassified drug aqueous solution article chemical structure darkness high performance liquid chromatography luminescence photochemistry photolysis photooxidation priority journal quantum yield reaction analysis room temperature stoichiometry structure analysis thin layer chromatography ultraviolet spectrophotometry
Acceso en línea:	http://hdl.handle.net/20.500.12110/paper_0018019X_v87_n2_p349_Cabrerizo
Aporte de:	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires

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spelling	todo:paper_0018019X_v87_n2_p349_Cabrerizo2023-10-03T14:15:08Z Generation of Reactive Oxygen Species during the Photolysis of 6-(Hydroxymethyl)pterin in Alkaline Aqueous Solutions Cabrerizo, F.M. Thomas, A.H. Lorente, C. Dántola, M.L. Petroselli, G. Erra-Balsells, R. Capparelli, A.L. Alkali metals Amino acids Chromatography Methane Oxidation Oxygen Photochemical reactions Photolysis Solutions Spectrophotometry Stoichiometry Thermal effects Photoproducts Biodiversity 6 hydroxymethylpterin alkali hydrogen peroxide oxygen pterin 6 aldehyde pterin derivative reactive oxygen metabolite singlet oxygen unclassified drug aqueous solution article chemical structure darkness high performance liquid chromatography luminescence photochemistry photolysis photooxidation priority journal quantum yield reaction analysis room temperature stoichiometry structure analysis thin layer chromatography ultraviolet spectrophotometry Photochemical studies of the reactivity of 6-(hydroxymethyl)pterin (=2-amino-6-(hydroxymethyl)pteridin-4(1H)-one; HPT) in alkaline aqueous solutions (pH 10.2-10.8) at 350 nm and room temperature were performed. The photochemical reactions were followed by UV/VIS spectrophotometry, thin-layer chromatography (TLC), high-performance liquid chromatography (HPLC), and an enzymatic method for H2O2 determination. In the presence of O2, 6-formylpterin (=2-amino-3,4-dihydro-4-oxopteridine-6-carboxaldehyde; FPT) was the only photoproduct detected. In the absence of O2, we observed a compound with an absorbance maximum at 480 nm, which was oxidized very rapidly by O 2 in a dark reaction to yield FPT. The quantum yields of substrates disappearance and of photoproducts formation were determined. The formation of H2O2 during photooxidation was monitored, and the number of mol of H2O2 released per mol of HPT consumed corresponded to a 1: 1 stoichiometry. HPT was also investigated for efficiency of singlet-oxygen (1O2) production and quenching in aqueous solution. The quantum yield of 1O2 production (ΦΔ = 0.21 ± 0.01) was determined by measurements of the 1O2 luminescence in the near-IR (1270 nm) upon continuous excitation of the sensitizer. The rate constant of 1O 2 total quenching by HPT was determined (kt = 3.1 · 106 M-1 s-1), indicating that this compound was able to quench 1O2. However, 1O2 did not participate in the photooxidation of HPT to FPT. Fil:Erra-Balsells, R. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_0018019X_v87_n2_p349_Cabrerizo
institution	Universidad de Buenos Aires
institution_str	I-28
repository_str	R-134
collection	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic	Alkali metals Amino acids Chromatography Methane Oxidation Oxygen Photochemical reactions Photolysis Solutions Spectrophotometry Stoichiometry Thermal effects Photoproducts Biodiversity 6 hydroxymethylpterin alkali hydrogen peroxide oxygen pterin 6 aldehyde pterin derivative reactive oxygen metabolite singlet oxygen unclassified drug aqueous solution article chemical structure darkness high performance liquid chromatography luminescence photochemistry photolysis photooxidation priority journal quantum yield reaction analysis room temperature stoichiometry structure analysis thin layer chromatography ultraviolet spectrophotometry
spellingShingle	Alkali metals Amino acids Chromatography Methane Oxidation Oxygen Photochemical reactions Photolysis Solutions Spectrophotometry Stoichiometry Thermal effects Photoproducts Biodiversity 6 hydroxymethylpterin alkali hydrogen peroxide oxygen pterin 6 aldehyde pterin derivative reactive oxygen metabolite singlet oxygen unclassified drug aqueous solution article chemical structure darkness high performance liquid chromatography luminescence photochemistry photolysis photooxidation priority journal quantum yield reaction analysis room temperature stoichiometry structure analysis thin layer chromatography ultraviolet spectrophotometry Cabrerizo, F.M. Thomas, A.H. Lorente, C. Dántola, M.L. Petroselli, G. Erra-Balsells, R. Capparelli, A.L. Generation of Reactive Oxygen Species during the Photolysis of 6-(Hydroxymethyl)pterin in Alkaline Aqueous Solutions
topic_facet	Alkali metals Amino acids Chromatography Methane Oxidation Oxygen Photochemical reactions Photolysis Solutions Spectrophotometry Stoichiometry Thermal effects Photoproducts Biodiversity 6 hydroxymethylpterin alkali hydrogen peroxide oxygen pterin 6 aldehyde pterin derivative reactive oxygen metabolite singlet oxygen unclassified drug aqueous solution article chemical structure darkness high performance liquid chromatography luminescence photochemistry photolysis photooxidation priority journal quantum yield reaction analysis room temperature stoichiometry structure analysis thin layer chromatography ultraviolet spectrophotometry
description	Photochemical studies of the reactivity of 6-(hydroxymethyl)pterin (=2-amino-6-(hydroxymethyl)pteridin-4(1H)-one; HPT) in alkaline aqueous solutions (pH 10.2-10.8) at 350 nm and room temperature were performed. The photochemical reactions were followed by UV/VIS spectrophotometry, thin-layer chromatography (TLC), high-performance liquid chromatography (HPLC), and an enzymatic method for H2O2 determination. In the presence of O2, 6-formylpterin (=2-amino-3,4-dihydro-4-oxopteridine-6-carboxaldehyde; FPT) was the only photoproduct detected. In the absence of O2, we observed a compound with an absorbance maximum at 480 nm, which was oxidized very rapidly by O 2 in a dark reaction to yield FPT. The quantum yields of substrates disappearance and of photoproducts formation were determined. The formation of H2O2 during photooxidation was monitored, and the number of mol of H2O2 released per mol of HPT consumed corresponded to a 1: 1 stoichiometry. HPT was also investigated for efficiency of singlet-oxygen (1O2) production and quenching in aqueous solution. The quantum yield of 1O2 production (ΦΔ = 0.21 ± 0.01) was determined by measurements of the 1O2 luminescence in the near-IR (1270 nm) upon continuous excitation of the sensitizer. The rate constant of 1O 2 total quenching by HPT was determined (kt = 3.1 · 106 M-1 s-1), indicating that this compound was able to quench 1O2. However, 1O2 did not participate in the photooxidation of HPT to FPT.
format	JOUR
author	Cabrerizo, F.M. Thomas, A.H. Lorente, C. Dántola, M.L. Petroselli, G. Erra-Balsells, R. Capparelli, A.L.
author_facet	Cabrerizo, F.M. Thomas, A.H. Lorente, C. Dántola, M.L. Petroselli, G. Erra-Balsells, R. Capparelli, A.L.
author_sort	Cabrerizo, F.M.
title	Generation of Reactive Oxygen Species during the Photolysis of 6-(Hydroxymethyl)pterin in Alkaline Aqueous Solutions
title_short	Generation of Reactive Oxygen Species during the Photolysis of 6-(Hydroxymethyl)pterin in Alkaline Aqueous Solutions
title_full	Generation of Reactive Oxygen Species during the Photolysis of 6-(Hydroxymethyl)pterin in Alkaline Aqueous Solutions
title_fullStr	Generation of Reactive Oxygen Species during the Photolysis of 6-(Hydroxymethyl)pterin in Alkaline Aqueous Solutions
title_full_unstemmed	Generation of Reactive Oxygen Species during the Photolysis of 6-(Hydroxymethyl)pterin in Alkaline Aqueous Solutions
title_sort	generation of reactive oxygen species during the photolysis of 6-(hydroxymethyl)pterin in alkaline aqueous solutions
url	http://hdl.handle.net/20.500.12110/paper_0018019X_v87_n2_p349_Cabrerizo
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_version_	1782028850275811328

Generation of Reactive Oxygen Species during the Photolysis of 6-(Hydroxymethyl)pterin in Alkaline Aqueous Solutions

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