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spelling paper:paper_0018019X_v87_n2_p349_Cabrerizo2023-06-08T14:39:10Z Generation of Reactive Oxygen Species during the Photolysis of 6-(Hydroxymethyl)pterin in Alkaline Aqueous Solutions Erra Balsells, Rosa 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. 2004 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_0018019X_v87_n2_p349_Cabrerizo 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
Erra Balsells, Rosa
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.
author Erra Balsells, Rosa
author_facet Erra Balsells, Rosa
author_sort Erra Balsells, Rosa
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
publishDate 2004
url https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_0018019X_v87_n2_p349_Cabrerizo
http://hdl.handle.net/20.500.12110/paper_0018019X_v87_n2_p349_Cabrerizo
work_keys_str_mv AT errabalsellsrosa generationofreactiveoxygenspeciesduringthephotolysisof6hydroxymethylpterininalkalineaqueoussolutions
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