Oxidation of 2′-deoxyguanosine 5′-monophosphate photoinduced by pterin: Type I versus type II mechanism
UV-A radiation (320-400 nm) induces damage to the DNA molecule and its components through different photosensitized reactions. Among these processes, photosensitized oxidations may occur through electron transfer or hydrogen abstraction (type I) and/or the production of singlet molecular oxygen ( 1O...
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2008
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| Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00027863_v130_n10_p3001_Petroselli http://hdl.handle.net/20.500.12110/paper_00027863_v130_n10_p3001_Petroselli |
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paper:paper_00027863_v130_n10_p3001_Petroselli2023-06-08T14:22:43Z Oxidation of 2′-deoxyguanosine 5′-monophosphate photoinduced by pterin: Type I versus type II mechanism Hydrogen Molecular oxygen Oxidation Photosensitizers Ultraviolet radiation Heterocyclic compounds Hydrogen abstraction Photosensitized oxidations Phosphates deoxyguanosine phosphate heterocyclic compound hydrogen oxygen photosensitizing agent pterin singlet oxygen 2'-deoxyguanosine 5'-phosphate pterin derivative singlet oxygen unclassified drug acidity alkalinity animal tissue aqueous solution article chemical reaction concentration (parameters) electron transport energy transfer high performance liquid chromatography kinetics luminescence nonhuman oxidation pH photosensitization steady state ultraviolet A radiation ultraviolet irradiation chemistry oxidation reduction reaction photochemistry radiation exposure time ultraviolet radiation Deoxyguanine Nucleotides Electron Transport Kinetics Oxidation-Reduction Photochemistry Pterins Singlet Oxygen Time Factors Ultraviolet Rays UV-A radiation (320-400 nm) induces damage to the DNA molecule and its components through different photosensitized reactions. Among these processes, photosensitized oxidations may occur through electron transfer or hydrogen abstraction (type I) and/or the production of singlet molecular oxygen ( 1O2) (type II). Pterins, heterocyclic compounds widespread in biological systems, participate in relevant biological processes and are able to act as photosensitizers. We have investigated the photosensitized oxidation of 2′-deoxyguanosine 5′-monophosphate (dGMP) by pterin (PT) in aqueous solution under UV-A irrradiation. Kinetic analysis was employed to evaluate the participation of both types of mechanism under different pH conditions. The rate constant of 1O2 total quenching (kt) by dGMP was determined by steady-state analysis of the 1O2 NIR luminescence, whereas the rate constant of the chemical reaction between 1O2 and dGMP (kr) was evaluated from kinetic analysis of concentration profiles obtained by HPLC. The results show that the oxidation of dGMP photosensitized by PT occurs through two competing mechanisms that contribute in different proportions depending on the pH. The dominant mechanism in alkaline media involves the reaction of dGMP with 1O2 produced by energy transfer from the PT triplet state to molecular oxygen (type II). In contrast, under acidic pH conditions, where PT and the guanine moiety of dGMP are not ionized, the main pathway for dGMP oxidation involves an initial electron transfer between dGMP and the PT triplet state (type I mechanism). The biological implications of the results obtained are also discussed. © 2008 American Chemical Society. 2008 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00027863_v130_n10_p3001_Petroselli http://hdl.handle.net/20.500.12110/paper_00027863_v130_n10_p3001_Petroselli |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
Hydrogen Molecular oxygen Oxidation Photosensitizers Ultraviolet radiation Heterocyclic compounds Hydrogen abstraction Photosensitized oxidations Phosphates deoxyguanosine phosphate heterocyclic compound hydrogen oxygen photosensitizing agent pterin singlet oxygen 2'-deoxyguanosine 5'-phosphate pterin derivative singlet oxygen unclassified drug acidity alkalinity animal tissue aqueous solution article chemical reaction concentration (parameters) electron transport energy transfer high performance liquid chromatography kinetics luminescence nonhuman oxidation pH photosensitization steady state ultraviolet A radiation ultraviolet irradiation chemistry oxidation reduction reaction photochemistry radiation exposure time ultraviolet radiation Deoxyguanine Nucleotides Electron Transport Kinetics Oxidation-Reduction Photochemistry Pterins Singlet Oxygen Time Factors Ultraviolet Rays |
| spellingShingle |
Hydrogen Molecular oxygen Oxidation Photosensitizers Ultraviolet radiation Heterocyclic compounds Hydrogen abstraction Photosensitized oxidations Phosphates deoxyguanosine phosphate heterocyclic compound hydrogen oxygen photosensitizing agent pterin singlet oxygen 2'-deoxyguanosine 5'-phosphate pterin derivative singlet oxygen unclassified drug acidity alkalinity animal tissue aqueous solution article chemical reaction concentration (parameters) electron transport energy transfer high performance liquid chromatography kinetics luminescence nonhuman oxidation pH photosensitization steady state ultraviolet A radiation ultraviolet irradiation chemistry oxidation reduction reaction photochemistry radiation exposure time ultraviolet radiation Deoxyguanine Nucleotides Electron Transport Kinetics Oxidation-Reduction Photochemistry Pterins Singlet Oxygen Time Factors Ultraviolet Rays Oxidation of 2′-deoxyguanosine 5′-monophosphate photoinduced by pterin: Type I versus type II mechanism |
| topic_facet |
Hydrogen Molecular oxygen Oxidation Photosensitizers Ultraviolet radiation Heterocyclic compounds Hydrogen abstraction Photosensitized oxidations Phosphates deoxyguanosine phosphate heterocyclic compound hydrogen oxygen photosensitizing agent pterin singlet oxygen 2'-deoxyguanosine 5'-phosphate pterin derivative singlet oxygen unclassified drug acidity alkalinity animal tissue aqueous solution article chemical reaction concentration (parameters) electron transport energy transfer high performance liquid chromatography kinetics luminescence nonhuman oxidation pH photosensitization steady state ultraviolet A radiation ultraviolet irradiation chemistry oxidation reduction reaction photochemistry radiation exposure time ultraviolet radiation Deoxyguanine Nucleotides Electron Transport Kinetics Oxidation-Reduction Photochemistry Pterins Singlet Oxygen Time Factors Ultraviolet Rays |
| description |
UV-A radiation (320-400 nm) induces damage to the DNA molecule and its components through different photosensitized reactions. Among these processes, photosensitized oxidations may occur through electron transfer or hydrogen abstraction (type I) and/or the production of singlet molecular oxygen ( 1O2) (type II). Pterins, heterocyclic compounds widespread in biological systems, participate in relevant biological processes and are able to act as photosensitizers. We have investigated the photosensitized oxidation of 2′-deoxyguanosine 5′-monophosphate (dGMP) by pterin (PT) in aqueous solution under UV-A irrradiation. Kinetic analysis was employed to evaluate the participation of both types of mechanism under different pH conditions. The rate constant of 1O2 total quenching (kt) by dGMP was determined by steady-state analysis of the 1O2 NIR luminescence, whereas the rate constant of the chemical reaction between 1O2 and dGMP (kr) was evaluated from kinetic analysis of concentration profiles obtained by HPLC. The results show that the oxidation of dGMP photosensitized by PT occurs through two competing mechanisms that contribute in different proportions depending on the pH. The dominant mechanism in alkaline media involves the reaction of dGMP with 1O2 produced by energy transfer from the PT triplet state to molecular oxygen (type II). In contrast, under acidic pH conditions, where PT and the guanine moiety of dGMP are not ionized, the main pathway for dGMP oxidation involves an initial electron transfer between dGMP and the PT triplet state (type I mechanism). The biological implications of the results obtained are also discussed. © 2008 American Chemical Society. |
| title |
Oxidation of 2′-deoxyguanosine 5′-monophosphate photoinduced by pterin: Type I versus type II mechanism |
| title_short |
Oxidation of 2′-deoxyguanosine 5′-monophosphate photoinduced by pterin: Type I versus type II mechanism |
| title_full |
Oxidation of 2′-deoxyguanosine 5′-monophosphate photoinduced by pterin: Type I versus type II mechanism |
| title_fullStr |
Oxidation of 2′-deoxyguanosine 5′-monophosphate photoinduced by pterin: Type I versus type II mechanism |
| title_full_unstemmed |
Oxidation of 2′-deoxyguanosine 5′-monophosphate photoinduced by pterin: Type I versus type II mechanism |
| title_sort |
oxidation of 2′-deoxyguanosine 5′-monophosphate photoinduced by pterin: type i versus type ii mechanism |
| publishDate |
2008 |
| url |
https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00027863_v130_n10_p3001_Petroselli http://hdl.handle.net/20.500.12110/paper_00027863_v130_n10_p3001_Petroselli |
| _version_ |
1768546279928889344 |