51
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Liu L, Yang D, Li P. pH-Related and Site-Specific Excited-State Proton Transfer from Pterin to Acetate. J Phys Chem B 2014; 118:11707-14. [DOI: 10.1021/jp5082017] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Lei Liu
- State Key Laboratory of Molecular
Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
- State Key Laboratory
of Fine Chemicals, Dalian University of Technology, Dalian 116024, China
| | - Dapeng Yang
- State Key Laboratory of Molecular
Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
- Physics Laboratory, North China University of Water Resources and Electric Power, Zhengzhou 450045, China
| | - Peng Li
- State Key Laboratory of Molecular
Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
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52
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Zhang J, Liu Y, Liu X, Li Y, Yin X, Subirade M, Zhou P, Liang L. The folic acid/β-casein complex: Characteristics and physicochemical implications. Food Res Int 2014. [DOI: 10.1016/j.foodres.2014.01.019] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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53
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Juzeniene A, Thu Tam TT, Iani V, Moan J. The action spectrum for folic acid photodegradation in aqueous solutions. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2013; 126:11-6. [DOI: 10.1016/j.jphotobiol.2013.05.011] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2013] [Revised: 05/08/2013] [Accepted: 05/29/2013] [Indexed: 12/14/2022]
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54
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Serrano MP, Borsarelli CD, Thomas AH. Type I photosensitization of 2'-deoxyadenosine 5'-monophosphate (5'-dAMP) by biopterin and its photoproduct formylpterin. Photochem Photobiol 2013; 89:1456-62. [PMID: 23837607 DOI: 10.1111/php.12134] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2013] [Accepted: 07/03/2013] [Indexed: 11/30/2022]
Abstract
Biopterin (Bip) and its photoproducts 6-formylpterin (Fop) and 6-carboxypterin (Cap) accumulate in the skin of patients suffering from vitiligo, a chronic depigmentation disorder where the protection against UV radiation fails because of the lack of melanin. These compounds absorb in the UV-A inducing a potential photosensitizing action that can cause damage to DNA and other biomolecules. In this work, we have investigated the capability of these pterin derivatives (Pt) to act as photosensitizers under UV-A irradiation for the degradation of 2'-deoxyadenosine 5'-monophosphate (5'-dAMP) in aqueous solutions, as model DNA target. Steady-state and time-resolved experiments were performed and the effect of pH was evaluated. The results showed that photosensitized degradation of 5'-dAMP was only observed under acidic conditions, and a mechanistic analysis revealed the participation of the triplet excited state of the pterin derivatives ((3)Pt*) by electron transfer yielding the corresponding pair of radical ions (Pt(•-) and 5'-dAMP(•+)), with successive photosensitizer recovery by electron transfer from Pt(•-) to O2. Finally, 5'-dAMP(•+) participates in subsequent reactions to yield degradation products.
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Affiliation(s)
- Mariana P Serrano
- Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), Departamento de Química, Facultad de Ciencias Exactas, Universidad Nacional de La Plata (UNLP), CCT La Plata-CONICET, La Plata, Argentina
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55
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Ding X, Yao P. Soy protein/soy polysaccharide complex nanogels: folic acid loading, protection, and controlled delivery. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:8636-44. [PMID: 23758109 DOI: 10.1021/la401664y] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
In this study, we developed a facile approach to produce nanogels via self-assembly of folic acid, soy protein, and soy polysaccharide. High-pressure homogenization was introduced to break down the original aggregates of soy protein, which benefits the binding of soy protein with soy polysaccharide and folic acid at pH 4.0. After a heat treatment that causes the soy protein denaturation and gelation, folic acid-loaded soy protein/soy polysaccharide complex nanogels were fabricated. The nanogels have a polysaccharide surface that makes the nanogels dispersible in acidic conditions where folic acid is insoluble and soy protein forms precipitates after heating. More importantly, the protein and polysaccharide can inhibit the reactions between dissolved oxygen and folic acid during UV irradiation. After the preparation and storage of the nanogels in the presence of heat, oxygen, and light in acidic conditions, most of the folic acid molecules in the nanogels remain in their natural structure and can be released rapidly at neutral pH, that is, in the intestine. Because most food and beverages are acidic, the nanogels are a suitable delivery system of folic acid in food and beverages.
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Affiliation(s)
- Xuzhe Ding
- State Key Laboratory of Molecular Engineering of Polymers and Department of Macromolecular Science, Fudan University, Shanghai 200433, China
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56
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Zhang L, Tian L, Ye Z, Song B, Yuan J. Preparation of visible-light-excited europium biolabels for time-resolved luminescence cell imaging application. Talanta 2013; 108:143-9. [DOI: 10.1016/j.talanta.2013.02.065] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Revised: 02/21/2013] [Accepted: 02/27/2013] [Indexed: 10/27/2022]
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57
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Liang L, Zhang J, Zhou P, Subirade M. Protective effect of ligand-binding proteins against folic acid loss due to photodecomposition. Food Chem 2013; 141:754-61. [PMID: 23790844 DOI: 10.1016/j.foodchem.2013.03.044] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2012] [Revised: 03/04/2013] [Accepted: 03/13/2013] [Indexed: 10/27/2022]
Abstract
The B group vitamin known as folates is essential for a variety of physiological processes and plays an important role in the prevention of neural tube defects. However, it decomposes when exposed to UV light. In this study, the response of the synthetic form of folates known as folic acid to UV irradiation in the presence of β-lactoglobulin (β-LG), bovine serum albumin (BSA) and α-lactalbumin (α-LA) was investigated using circular dichroism, absorbance and fluorescence spectroscopy. Photodecomposition of folic acid was delayed in the presence of the proteins, which ranked in the order β-LG>BSA>α-LA in terms of effectiveness. Protein unfolding or decomposition occurred at the same time, due to interaction with folic acid photodecomposition products. The results suggest potential uses of ligand-binding proteins as carriers of water-soluble active compounds for nutraceutical applications.
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Affiliation(s)
- Li Liang
- State Key Lab of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, China
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58
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Thomas AH, Lorente C, Roitman K, Morales MM, Dántola ML. Photosensitization of bovine serum albumin by pterin: A mechanistic study. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2013; 120:52-8. [DOI: 10.1016/j.jphotobiol.2013.01.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2012] [Revised: 01/14/2013] [Accepted: 01/15/2013] [Indexed: 10/27/2022]
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Abstract
BACKGROUND Lateral flow assays (LFAs) are popular point-of-care diagnostic tools because they are rapid and easy to use. Nevertheless, they often lack analytical sensitivity and quantitative output and may be difficult to multiplex, limiting their usefulness in biomarker measurement. As a proof-of-concept study, we detail the design of a quantitative, multiplex LFA with readily available near-infrared (NIR) detection to improve analytical sensitivity. METHODS NIR dye was conjugated to selected antibodies and incorporated into LFAs. We used singleplex, optimized NIR-LFAs to measure interleukin (IL)-6 from 0 to 200 pg/mL and developed duplex assays to simultaneously measure IL-6 from 0 to 100 pg/mL (0 to 4.5 pmol/L) and C-reactive protein (CRP) from 50 to 2500 ng/mL (0.4 to 20 nmol/L) on a single test strip. Assays were tested on 60 different spiked samples and compared to ELISA results. RESULTS NIR-LFAs detected IL-6 in a 10% plasma matrix with a limit of detection of 4 pg/mL (182 fmol/L) and a CV <7%. Duplex NIR-LFAs quantitatively measured IL-6 and CRP concentrations simultaneously. Values strongly correlated to ELISA measurements, with R(2) values of 0.9825 and 0.9711 for IL-6 and CRP, respectively. CONCLUSIONS NIR-LFAs exhibit quantitative measurement at pg/mL concentrations owing to a high signal-to-background ratio and robust detection antibody clearance through the test strip. Moreover, NIR-LFAs are able to detect molecules present at vastly different concentrations in multiplex format and compare favorably to ELISAs. LFAs with direct NIR detection may be a valuable tool for biomarker evaluation in the point-of-care setting.
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60
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Saleh N, Graham J, Afaneh A, Al-Soud YA, Schreckenbach G, Esmadi FT. Pteridine-based fluorescent pH sensors designed for physiological applications. J Photochem Photobiol A Chem 2012. [DOI: 10.1016/j.jphotochem.2012.08.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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61
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Serrano MP, Lorente C, Vieyra FEM, Borsarelli CD, Thomas AH. Photosensitizing properties of biopterin and its photoproducts using 2'-deoxyguanosine 5'-monophosphate as an oxidizable target. Phys Chem Chem Phys 2012; 14:11657-65. [PMID: 22825359 DOI: 10.1039/c2cp41476g] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
UV-A radiation (320-400 nm) induces damage to the DNA molecule and its components through photosensitized reactions. Biopterin (Bip) and its photoproducts 6-formylpterin (Fop) and 6-carboxypterin (Cap) accumulate in the skin of human beings suffering from vitiligo, a depigmentation disorder where the protection against UV radiation fails because of the lack of melanin. This study was aimed to evaluate the photosensitizing properties of oxidized pterins present in the skin and to elucidate the mechanisms involved in the photosensitized oxidation of purine nucleotides by pterins in vitro. For this purpose, steady-state and time-resolved experiments in acidic (pH 5.0-5.8) aqueous solution were performed using Bip, Fop and Cap as photosensitizers and the nucleotide 2'-deoxyguanosine 5'-monophosphate (dGMP) as an oxidizable target. The three pterin derivatives are able to photosensitize dGMP, being Fop the most efficient sensitizer. The reactions proceed through two competing pathways: (1) electron transfer from dGMP to triplet excited-state of pterins (type I mechanism) and (2) reaction of dGMP with (1)O(2) produced by pterins (type II mechanism). Kinetic analysis revealed that the electron transfer pathway is the main mechanism and the interaction of dGMP with the triplet excited-state of pterins and the formation of the corresponding dGMP radicals were demonstrated by laser flash photolysis experiments. The biological implications of the results obtained are also discussed.
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Affiliation(s)
- Mariana P Serrano
- Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), Departamento de Química, Facultad de Ciencias Exactas, Universidad Nacional de La Plata (UNLP), CCT La Plata-CONICET, La Plata, Argentina
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62
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Rate constants of quenching of the fluorescence of pterins by the iodide anion in aqueous solution. Chem Phys Lett 2012. [DOI: 10.1016/j.cplett.2012.06.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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63
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Turkowski V, Babu S, Le D, Kumar A, Haldar MK, Wagh AV, Hu Z, Karakoti AS, Gesquiere AJ, Law B, Mallik S, Rahman TS, Leuenberger MN, Seal S. Linker-induced anomalous emission of organic-molecule conjugated metal-oxide nanoparticles. ACS NANO 2012; 6:4854-4863. [PMID: 22559229 DOI: 10.1021/nn301316j] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Semiconductor nanoparticles conjugated with organic- and dye-molecules to yield high efficiency visible photoluminescence (PL) hold great potential for many future technological applications. We show that folic acid (FA)-conjugated to nanosize TiO(2) and CeO(2) particles demonstrates a dramatic increase of photoemission intensity at wavelengths between 500 and 700 nm when derivatized using aminopropyl trimethoxysilane (APTMS) as spacer-linker molecules between the metal oxide and FA. Using density-functional theory (DFT) and time-dependent DFT calculations we demonstrate that the strong increase of the PL can be explained by electronic transitions between the titania surface oxygen vacancy (OV) states and the low-energy excited states of the FA/APTMS molecule anchored onto the surface oxygen bridge sites in close proximity to the OVs. We suggest this scenario to be a universal feature for a wide class of metal oxide nanoparticles, including nanoceria, possessing a similar band gap (∼3 eV) and with a large surface-vacancy-related density of electronic states. We demonstrate that the molecule-nanoparticle linker can play a crucial role in tuning the electronic and optical properties of nanosystems by bringing optically active parts of the molecule and of the surface close to each other.
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Affiliation(s)
- Volodymyr Turkowski
- Department of Physics, University of Central Florida, Orlando, Florida 32816, USA
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64
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Li G, Magana D, Dyer RB. Photoinduced electron transfer in folic acid investigated by ultrafast infrared spectroscopy. J Phys Chem B 2012; 116:3467-75. [PMID: 22364409 PMCID: PMC3311227 DOI: 10.1021/jp300392a] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Conformational control of excited-state intramolecular electron transfer (ET) in folic acid (FA) has been investigated using femtosecond time-resolved infrared (TRIR) spectroscopy. Ultrafast excited-state ET between the pterin and the 4-aminobenzoyl subunits of FA is observed for the anionic form (at pH 10.0). An ET lifetime of 2.5 ps is estimated from Marcus theory for FA in the "U" conformation, in close agreement with the observed lifetime of 2.0 ps. Return to the ground state through the reverse ET reaction happens almost as rapidly, within 5 ps, resulting in rapid quenching of the singlet excited state. In mixed water:dimethyl sulfoxide solvent, ET becomes more unfavorable as FA adopts a more open conformation, thereby increasing the effective donor-acceptor distance and reducing the coupling energy. In contrast, no ET is observed for the cationic form of FA at low pH (6.0). In this case, the initial singlet excited state is localized on the pterin moiety of FA, and the excited-state charge distribution evolves with time. The charge redistribution in the pterin that occurs with intersystem crossing to the triplet state is characterized by changes in the transient IR spectrum. The excited-state lifetime is much longer in the absence of an ET quenching pathway. These results provide new insight into the mechanism of photodegradation and toxicity of FA. Ultrafast intramolecular ET in closed conformations of FA rapidly quenches the excited state and prevents efficient triplet state formation. Thus, conformations of FA that allow ultrafast intra-ET and rapid quenching of the singlet excited state play a key role in inhibiting pathological pathways following photoexcitation of FA.
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Affiliation(s)
- Guifeng Li
- Department of Chemistry, Emory University, Atlanta, Georgia, 30322, United States
| | - Donny Magana
- Department of Chemistry, Emory University, Atlanta, Georgia, 30322, United States
| | - R. Brian Dyer
- Department of Chemistry, Emory University, Atlanta, Georgia, 30322, United States
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65
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Zhou C, Kunzmann A, Rakonjac M, Fadeel B, Garcia-Bennett A. Morphological properties of nanoporous folic acid materials and in vitro assessment of their biocompatibility. Nanomedicine (Lond) 2012; 7:327-34. [DOI: 10.2217/nnm.11.109] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Background: Mesoporous silica-based particles are of potential interest for the development of novel therapeutic targeted delivery vehicles. Their ability to load and release large quantities of active pharmaceutical products with varying properties, combining controlled and targeted release functions make them unique amongst nanotechnology-based carrier systems. Materials & methods: In this study, nanoporous folic acid-templated materials (NFM-1) were prepared and the synthetic strategies for the control of textural and morphology properties of NFM-1 are described. The potential biocompatibility of NFM-1 particles with different morphology (gyroid shaped, fibers and rod-shaped) was assessed using a panel of human cell lines. Results: The results reveal that NFM-1 morphology has an impact on cell viability such that particles showing higher aspect ratios possess increased cytotoxicity. Conclusion: These studies provide useful information for the development of novel mesoporous materials for biomedical applications, including cell-specific drug delivery. Original submitted: 12 April 2011; Revised submitted: 25 May 2011
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Affiliation(s)
- Chunfang Zhou
- Nanologica AB, Drottning Kristinas Väg 45, SE-114 28 Stockholm, Sweden
| | - Andrea Kunzmann
- Division of Molecular Toxicology, Institute of Environmental Medicine, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Marija Rakonjac
- Division of Molecular Toxicology, Institute of Environmental Medicine, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Bengt Fadeel
- Division of Molecular Toxicology, Institute of Environmental Medicine, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Alfonso Garcia-Bennett
- Nanotechnology and Functional Materials, Department of Engineering Sciences, Ångstrom Laboratory, Uppsala University, Box 534, SE-75121 Uppsala, Sweden
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66
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Serrano MP, Vignoni M, Dántola ML, Oliveros E, Lorente C, Thomas AH. Emission properties of dihydropterins in aqueous solutions. Phys Chem Chem Phys 2011; 13:7419-25. [PMID: 21409193 DOI: 10.1039/c0cp02912b] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2023]
Abstract
Pterins belong to a class of heterocyclic compounds present in a wide range of living systems and accumulate in the skin of patients affected by vitiligo, a depigmentation disorder. The study of the emission of 7,8-dihydropterins is difficult because these compounds are more or less unstable in the presence of O(2) and their solutions are contaminated with oxidized pterins which have much higher fluorescence quantum yields (Φ(F)). In this work, the emission properties of six compounds of the dihydropterin family (6-formyl-7,8-dihydropterin (H(2)Fop), sepiapterin (Sep), 7,8-dihydrobiopterin (H(2)Bip), 7,8-dihydroneopterin (H(2)Nep), 6-hydroxymethyl-7,8-dihydropterin (H(2)Hmp), and 6-methyl-7,8-dihydropterin (H(2)Mep)) have been studied in aqueous solution. The fluorescence characteristics (spectra, Φ(F), lifetimes (τ(F))) of the neutral form of these compounds have been investigated using the single-photon-counting technique. Φ(F) and τ(F) values obtained lie in the ranges 3-9 × 10(-3) and 0.18-0.34 ns, respectively. The results are compared to those previously reported for oxidized pterins.
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Affiliation(s)
- Mariana P Serrano
- INIFTA, Departamento de Química, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, CCT La Plata-CONICET., C.C. 16, Suc. 4, (1900) La Plata, Argentina
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67
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Denofrio MP, Thomas AH, Lorente C. Oxidation of 2'-deoxyadenosine 5'-monophosphate photoinduced by lumazine. J Phys Chem A 2011; 114:10944-50. [PMID: 20873833 DOI: 10.1021/jp1061336] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
UV radiation induces damages to the DNA molecule and its components through photosensitized reactions. Among these processes, photosensitized oxidations may occur through electron transfer or hydrogen abstraction (type I mechanism) and/or the production of singlet molecular oxygen ((1)O(2)) (type II mechanism). Lumazines are an important family of heterocyclic compounds present in biological systems as biosynthetic precursors and/or products of metabolic degradation. To evaluate the capability of lumazines to act as photosensitizers through type I mechanism, we have investigated the oxidation of 2'-deoxyadenosine 5'-monophosphate (dAMP) photosensitized by the specific compound called lumazine (pteridine-2,4(1,3H)-dione; Lum) in aqueous solutions under UV irradiation. The photochemical reactions were followed by UV/vis spectrophotometry, HPLC, electrochemical measurement of dissolved O(2), and an enzymatic method for H(2)O(2) determination. The effect of pH was evaluated and the participation of oxygen was investigated. In aerated solutions, oxidation of dAMP photoinduced by the acid form of Lum (pH 5.5) takes place through a type I mechanism, in which the excitation of Lum is followed by an electron transfer from dAMP molecule to the Lum triplet excited state. During the process, O(2) is consumed and H(2)O(2) is generated, whereas the photosensitizer is not consumed. In contrast, no evidence of a photochemical reaction induced by the basic form of Lum (pH 10.5) was observed.
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Affiliation(s)
- M Paula Denofrio
- Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), Departamento de Química, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, CCT La Plata-CONICET, Boulevard 113 y 64, 1900 La Plata, Argentina
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68
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Paula Denofrio M, Lorente C, Breitenbach T, Hatz S, Cabrerizo FM, Thomas AH, Ogilby PR. Photodynamic Effects of Pterin on HeLa Cells. Photochem Photobiol 2011; 87:862-6. [DOI: 10.1111/j.1751-1097.2011.00922.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- M. Paula Denofrio
- Departamento de Química, Facultad de Ciencias Exactas, Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), Universidad Nacional de La Plata, CCT La Plata‐CONICET, La Plata, Argentina
| | - Carolina Lorente
- Departamento de Química, Facultad de Ciencias Exactas, Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), Universidad Nacional de La Plata, CCT La Plata‐CONICET, La Plata, Argentina
| | - Thomas Breitenbach
- Department of Chemistry, Center for Oxygen Microscopy and Imaging, University of Aarhus, Århus, Denmark
| | - Sonja Hatz
- Department of Chemistry, Center for Oxygen Microscopy and Imaging, University of Aarhus, Århus, Denmark
| | - Franco M. Cabrerizo
- Instituto de Investigaciones Biotecnológicas, Instituto Tecnológico de Chascomús (IIB‐INTECH), Universidad Nacional de San Martín, CONICET, Camino Circunv., Chascomús, Argentina
| | - Andrés H. Thomas
- Departamento de Química, Facultad de Ciencias Exactas, Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), Universidad Nacional de La Plata, CCT La Plata‐CONICET, La Plata, Argentina
| | - Peter R. Ogilby
- Department of Chemistry, Center for Oxygen Microscopy and Imaging, University of Aarhus, Århus, Denmark
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69
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Kritsky MS, Telegina TA, Vechtomova YL, Kolesnikov MP, Lyudnikova TA, Golub OA. Excited flavin and pterin coenzyme molecules in evolution. BIOCHEMISTRY (MOSCOW) 2010; 75:1200-16. [DOI: 10.1134/s0006297910100020] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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70
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Petroselli G, Dántola ML, Cabrerizo FM, Lorente C, Braun AM, Oliveros E, Thomas AH. Quenching of the fluorescence of aromatic pterins by deoxynucleotides. J Phys Chem A 2010; 113:1794-9. [PMID: 19199487 DOI: 10.1021/jp8101496] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Steady-state and time-resolved studies of the fluorescence of four aromatic unconjugated pterins (pterin (Ptr), 6-(hydroxymethyl)pterin (Hmp), 6-methylpterin (Mep), and 6,7-dimethylpterin (Dmp)) in aqueous solutions in the presence of different nucleotides (2'-deoxyguanosine 5'-monophosphate (dGMP), 2'-deoxyadenosine 5'-monophosphate (dAMP), and 2'-deoxycytosine 5'-monophosphate (dCMP)) have been performed using the single-photon counting technique. The singlet excited states of acid forms of pterins are deactivated by purine nucleotides (dGMP and dAMP) via a combination of dynamic and static processes. The efficiency of the dynamic quenching is high, independently of the nature of the purine base of the nucleotide and of the chemical structure of the substituents linked to the pterin moiety. Analysis of the static quenching indicates that ground-state association between pterins and purine nucleotides takes place, but the formation of the corresponding complexes is significant only at relatively high reactant concentrations. The quenching of the fluorescence of acid forms of pterin derivatives by dCMP, a pyrimidine nucleotide, is slightly less efficient than the quenching by purine nucleotides and is purely dynamic. In alkaline media, the fluorescence quenching is much less efficient than in acidic media, the deactivation by purine nucleotides being purely dynamic, whereas quenching by dCMP is negligible. Possible mechanisms for the quenching of fluorescence of pterin derivatives by the different nucleotides are discussed.
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Affiliation(s)
- Gabriela Petroselli
- Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas, Departamento de Química, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, CCT La Plata-CONICET, Boulevard 113 y 64, 1900 La Plata, Argentina
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71
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Dántola ML, Denofrio MP, Zurbano B, Gimenez CS, Ogilby PR, Lorente C, Thomas AH. Mechanism of photooxidation of folic acid sensitized by unconjugated pterins. Photochem Photobiol Sci 2010; 9:1604-12. [PMID: 20922252 DOI: 10.1039/c0pp00210k] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Folic acid, or pteroyl-l-glutamic acid (PteGlu), is a precursor of coenzymes involved in the metabolism of nucleotides and amino acids. PteGlu is composed of three moieties: a 6-methylpterin (Mep) residue, a p-aminobenzoic acid (PABA) residue, and a glutamic acid (Glu) residue. Accumulated evidence indicates that photolysis of PteGlu leads to increased risk of several pathologies. Thus, a study of PteGlu photodegradation can have significant ramifications. When an air-equilibrated aqueous solution of PteGlu is exposed to UV-A radiation, the rate of the degradation increases with irradiation time. The mechanism involved in this "auto-photo-catalytic" effect was investigated in aqueous solutions using a variety of tools. Whereas PteGlu is photostable under anaerobic conditions, it is converted into 6-formylpterin (Fop) and p-aminobenzoyl-l-glutamic acid (PABA-Glu) in the presence of oxygen. As the reaction proceeds and enough Fop accumulates in the solution, a photosensitized electron-transfer process starts, where Fop photoinduces the oxidation of PteGlu to Fop, and H(2)O(2) is formed. This process also takes place with other pterins as photosensitizers. The results are discussed with the context of previous mechanisms for processes photosensitized by pterins, and their biological implications are evaluated.
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Affiliation(s)
- M Laura Dántola
- INIFTA, Departamento de Química, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, CCT La Plata-CONICET. C.C. 16, Suc. 4, (1900), La Plata, Argentina
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72
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Liang L, Subirade M. Beta-lactoglobulin/folic acid complexes: formation, characterization, and biological implication. J Phys Chem B 2010; 114:6707-12. [PMID: 20411963 DOI: 10.1021/jp101096r] [Citation(s) in RCA: 133] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Beta-lactoglobulin (beta-LG), the major whey protein in bovine milk, binds to a wide range of compounds. Folic acid (FA) is a synthetic form of the B group vitamin known as folates, which are essential cofactors for a variety of physiological processes. The interaction of beta-LG with FA was studied using fluorescence spectroscopy to determine the FA binding constant and mode and the influence of the protein on FA photodegradation. At < or = 20 microM FA, which may be the critical self-association concentration, the binding constant and number are 2.0 (+/-0.6) x 10(6) M(-1) and 1.30 (+/-0.03) when excited at 280 nm and 4.3 (+/-2.2) x 10(5) M(-1) and 1.17 (+/-0.04) at 295 nm, as determined by protein intrinsic fluorescence. FA binds to the surface of beta-LG, possibly in the groove between the alpha-helix and the beta-barrel. Fluorescence analysis of the pterin portion of FA shows that complexation with beta-LG improves FA photostability. It is suggested that beta-LG complexes could be used as an effective carrier of FA in functional foods.
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Affiliation(s)
- Li Liang
- Institut de recherche sur les nutraceutiques et les aliments fonctionnels (INAF/STELA), Université Laval, Québec, QC, Canada
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73
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Suriamoorthy P, Zhang X, Hao G, Joly AG, Singh S, Hossu M, Sun X, Chen W. Folic acid-CdTe quantum dot conjugates and their applications for cancer cell targeting. Cancer Nanotechnol 2010; 1:19-28. [PMID: 26069476 PMCID: PMC4451629 DOI: 10.1007/s12645-010-0003-3] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2010] [Accepted: 07/07/2010] [Indexed: 10/26/2022] Open
Abstract
In this study, we report the preparation, luminescence, and targeting properties of folic acid-CdTe quantum dot conjugates. Water-soluble CdTe quantum dots were synthesized and conjugated with folic acid using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide-N-hydroxysuccinimide chemistry. The influence of folic acid on the luminescence properties of CdTe quantum dots was investigated, and no energy transfer between them was observed. To investigate the efficiency of folic acid-CdTe nanoconjugates for tumor targeting, pure CdTe quantum dots and folic acid-coated CdTe quantum dots were incubated with human nasopharyngeal epidermal carcinoma cell line with positive expressing folic acid receptors (KB cells) and lung cancer cells without expression of folic acid receptors (A549 cells). For the cancer cells with positive folate receptors (KB cells), the uptake for CdTe quantum dots is very low, but for folic acid-CdTe nanoconjugates, the uptake is very high. For the lung cancer cells without folate receptors (A549 cells), the uptake for folic acid-CdTe nanoconjugates is also very low. The results indicate that folic acid is an effective targeting molecule for tumor cells with overexpressed folate receptors.
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Affiliation(s)
- Preethi Suriamoorthy
- />Department of Physics, The University of Texas at Arlington, Arlington, TX 76019-0059 USA
| | - Xing Zhang
- />Department of Physics, The University of Texas at Arlington, Arlington, TX 76019-0059 USA
| | - Guiyang Hao
- />Department of Radiology, The University of Texas Southwestern Medical Center, Dallas, TX USA
| | - Alan G. Joly
- />Pacific Northwest National Laboratory, Richland, WA 99352 USA
| | - Surya Singh
- />Department of Integrative Biology, University of California, Berkeley, CA 94720 USA
| | - Marius Hossu
- />Department of Physics, The University of Texas at Arlington, Arlington, TX 76019-0059 USA
| | - Xiankai Sun
- />Department of Radiology, The University of Texas Southwestern Medical Center, Dallas, TX USA
- />Advanced Imaging Research Center, The University of Texas Southwestern Medical Center, Dallas, TX USA
| | - Wei Chen
- />Department of Physics, The University of Texas at Arlington, Arlington, TX 76019-0059 USA
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74
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Vechtomova YL, Telegina TA, Kolesnikov MP, Kritsky MS. Photobiochemistry of folates: A photochemical reduction of folic acid. APPL BIOCHEM MICRO+ 2010. [DOI: 10.1134/s0003683810030154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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75
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Vignoni M, Cabrerizo FM, Lorente C, Claparols C, Oliveros E, Thomas AH. Photochemistry of dihydrobiopterin in aqueous solution. Org Biomol Chem 2010; 8:800-10. [PMID: 20135037 DOI: 10.1039/b913095k] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2023]
Abstract
Dihydrobiopterin (H(2)Bip) and its oxidized analogue, biopterin (Bip), accumulate in the skin of patients suffering from vitiligo, a chronic depigmentation disorder in which the protection against UV radiation fails. The photochemistry of H(2)Bip was studied in neutral aqueous solutions upon UV-A irradiation (320-400 nm) at room temperature. The photochemical reactions were followed by UV/vis spectrophotometry, HPLC and enzymatic methods for hydrogen peroxide (H(2)O(2)) determination. Photoproducts were analyzed by means of electrospray ionization mass spectrometry. Under anaerobic conditions, excitation of H(2)Bip leads to the formation of at least two isomeric dimers with molecular masses equal to exactly twice the molecular mass of the reactant. This reaction takes place from the singlet excited state of the reactant. To the best of our knowledge, this is the first time that the photodimerization of a dihydropterin is reported. In the presence of air, the dimers are again the main photoproducts at the beginning of the reaction, but a small proportion of the reactant is converted into Bip. As the reaction proceeds and enough Bip accumulates in the solution, a photosensitized process starts, where Bip photoinduces the oxidation of H(2)Bip to Bip, and H(2)O(2) is formed. As a consequence, the rates of H(2)Bip consumption and Bip formation increase as a function of irradiation time, resulting in an autocatalytic photochemical process. In this process, Bip in its triplet excited state reacts with the ground state of H(2)Bip. The mechanisms involved are analyzed and the biological implications of the results are discussed.
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Affiliation(s)
- Mariana Vignoni
- Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), Departamento de Química, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, CCT La Plata-CONICET, Casilla de Correo 16, Sucursal 4, (1900) La Plata, Argentina
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76
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77
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Goswami S, Hazra A, Jana S, Fun HK. Recognition study of substituted benzoic acids by 7-substituted pterin receptors in solution and solid phases. CrystEngComm 2010. [DOI: 10.1039/b917092h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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78
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Mori H, Nishinaka Y, Nonogawa M, Sommani P, Makino K, Yamashita K, Arai T. Substituent Effects of Pterin Derivatives on Singlet Oxygen Scavenging Activity. Biol Pharm Bull 2010; 33:905-8. [DOI: 10.1248/bpb.33.905] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Hiroko Mori
- Department of Anesthesia, Higashiyama Takeda Hospital
| | - Yoko Nishinaka
- School of Health Science, Faculty of Medicine, Kyoto University
| | | | | | | | - Kouhei Yamashita
- Department of Hematology and Oncology, Kyoto University Hospital
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79
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Martin CB, Walker D, Soniat M. Density functional theory study of possible mechanisms of folic acid photodecomposition. J Photochem Photobiol A Chem 2009. [DOI: 10.1016/j.jphotochem.2009.07.025] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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80
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Jaramillo P, Coutinho K, Canuto S. Solvent Effects in Chemical Processes. Water-Assisted Proton Transfer Reaction of Pterin in Aqueous Environment. J Phys Chem A 2009; 113:12485-95. [DOI: 10.1021/jp903638n] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Paula Jaramillo
- Instituto de Física, Universidade de São Paulo, CP 66318, 05314-970, São Paulo, SP, Brazil
| | - Kaline Coutinho
- Instituto de Física, Universidade de São Paulo, CP 66318, 05314-970, São Paulo, SP, Brazil
| | - Sylvio Canuto
- Instituto de Física, Universidade de São Paulo, CP 66318, 05314-970, São Paulo, SP, Brazil
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81
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Tyagi A, Penzkofer A, Batschauer A, Wolf E. Fluorescence behaviour of 5,10-methenyltetrahydrofolate, 10-formyltetrahydrofolate, 10-formyldihydrofolate, and 10-formylfolate in aqueous solution at pH 8. Chem Phys 2009. [DOI: 10.1016/j.chemphys.2009.05.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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82
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Hirakawa K. Fluorometry of singlet oxygen generated via a photosensitized reaction using folic acid and methotrexate. Anal Bioanal Chem 2008; 393:999-1005. [DOI: 10.1007/s00216-008-2522-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2008] [Revised: 11/06/2008] [Accepted: 11/10/2008] [Indexed: 10/21/2022]
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83
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Stokes RJ, McBride E, Wilson CG, Girkin JM, Smith WE, Graham D. Surface-enhanced Raman scattering spectroscopy as a sensitive and selective technique for the detection of folic acid in water and human serum. APPLIED SPECTROSCOPY 2008; 62:371-376. [PMID: 18416893 DOI: 10.1366/000370208784046812] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Surface-enhanced Raman scattering (SERS) is shown to give linear and sensitive concentration-dependent detection of folic acid using silver nanoparticles created via ethylene-diaminetetraacetic acid (EDTA) reduction. Optical detection by SERS overcomes the primary limitation of photodissociation encountered during the application of other shorter wavelength ultraviolet (UV)/near-UV techniques such as fluorescence based microscopy. The SERS approach in water-based samples was demonstrated and optimized using several longer wavelengths of excitation (514.5, 632.8, and 785 nm). Excitation in the green (514.5 nm) was found to achieve the best balance between photodissociation and SERS efficiency. Linear concentration dependence was observed in the range of 0.018 to 1 microM. The importance of folic acid in a clinical setting and the potential applications of this technique in a biological environment are highlighted. We demonstrate the potential to transfer this technique to real biological samples by the detection of folic acid in human serum samples by SERS.
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Affiliation(s)
- Robert J Stokes
- Centre for Molecular Nanometrology, WestCHEM, University of Strathclyde, Glasgow, UK
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84
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Petroselli G, Dántola ML, Cabrerizo FM, Capparelli AL, Lorente C, Oliveros E, Thomas AH. Oxidation of 2'-deoxyguanosine 5'-monophosphate photoinduced by pterin: type I versus type II mechanism. J Am Chem Soc 2008; 130:3001-11. [PMID: 18278909 DOI: 10.1021/ja075367j] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
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 ((1)O2) (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 (1)O2 total quenching (k(t)) by dGMP was determined by steady-state analysis of the (1)O2 NIR luminescence, whereas the rate constant of the chemical reaction between (1)O2 and dGMP (k(r)) 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 (1)O2 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.
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Affiliation(s)
- Gabriela Petroselli
- Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas, Departamento de Química, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, CONICET, Casilla de Correo 16, Sucursal 4, (1900) La Plata, Argentina
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85
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Arai T, Nonogawa M, Makino K, Endo N, Mori H, Miyoshi T, Yamashita K, Sasada M, Kakuyama M, Fukuda K. The Radical Scavenger Edaravone (3-Methyl-1-phenyl-2-pyrazolin-5-one) Reacts with a Pterin Derivative and Produces a Cytotoxic Substance That Induces Intracellular Reactive Oxygen Species Generation and Cell Death. J Pharmacol Exp Ther 2007; 324:529-38. [DOI: 10.1124/jpet.107.131391] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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86
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Anastasopoulos P, Mellos T, Spinou M, Tsiaka T, Timotheou‐Potamia M. Chemiluminometric and Fluorimetric Determination of Folic Acid. ANAL LETT 2007. [DOI: 10.1080/00032710701567022] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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87
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Chen X, Xu X, Cao Z. Theoretical Study on the Singlet Excited State of Pterin and Its Deactivation Pathway. J Phys Chem A 2007; 111:9255-62. [PMID: 17629256 DOI: 10.1021/jp0727502] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The excited-state properties and related photophysical processes of the acidic and basic forms of pterin have been investigated by the density functional theory and ab initio methodologies. The solvent effects on the low-lying states have been estimated by the polarized continuum model and combined QM/MM calculations. Calculations reveal that the observed two strong absorptions arise from the strong pi --> pi* transitions to 1(pipi*L(a)) and 1(pipi*L(b)) in the acidic and basic forms of pterin. The first 1(pipi*L(a)) excited state is exclusively responsible for the experimental emission band. The vertical 1(n(N)pi*) state with a small oscillator strength, slightly higher in energy than the 1(pipi*L(a)) state, is less accessible by the direct electronic transition. The 1(n(N)pi*) state may be involved in the photophysical process of the excited pterin via the 1(pipi*L(a)/n(N)pi*) conical intersection. The radiationless decay of the excited PT to the ground state experiences a barrier of 13.8 kcal/mol for the acidic form to reach the (S(1)/S(0)) conical intersection. Such internal conversion can be enhanced with the increase in excitation energy, which will reduce the fluorescence intensity as observed experimentally.
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Affiliation(s)
- Xing Chen
- Department of Chemistry and State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen 361005, China
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88
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Cabrerizo FM, Dántola ML, Petroselli G, Capparelli AL, Thomas AH, Braun AM, Lorente C, Oliveros E. Reactivity of Conjugated and Unconjugated Pterins with Singlet Oxygen (O2(1Δg)): Physical Quenching and Chemical Reaction†. Photochem Photobiol 2007; 83:526-34. [PMID: 17076587 DOI: 10.1562/2006-09-15-ra-1041] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Pterins (PTs) belong to a class of heterocyclic compounds present in a wide range of living systems. They participate in relevant biological functions and are involved in different photobiological processes. We have investigated the reactivity of conjugated PTs (folic acid [FA], 10-methylfolic acid [MFA], pteroic acid [PA]) and unconjugated PTs (PT, 6-hydroxymethylpterin [HPT], 6-methylpterin [MPT], 6,7-dimethylpterin [DPT], rhamnopterin [RPT]) with singlet oxygen (1O2) in aqueous solutions, and compared the efficiencies of chemical reaction and physical quenching. The chemical reactions between 1O2, produced by photosensitization, and PT derivatives were followed by UV-visible spectrophotometry and high-performance liquid chromatography, and corresponding rate constants (k(r)) were evaluated. Whenever possible, products were identified and quantified. Rate constants of 1O2 total quenching by the PT derivatives investigated were obtained from steady-state 1O2 luminescence measurements. Results show that the behavior of conjugated PTs differs considerably from that of unconjugated derivatives, and the mechanisms of 1O2 physical quenching by these compounds and of their chemical reaction with 1O2 are discussed in relation to their structural features.
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Affiliation(s)
- Franco M Cabrerizo
- Departamento de Química, Facultad de Ciencias Exactas, Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), Universidad Nacional de La Plata, CONICET, La Plata, Argentina
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89
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Gaweda S, Stochel G, Szaciłowski K. Bioinspired Nanodevice Based on the Folic Acid/Titanium Dioxide System. Chem Asian J 2007; 2:580-90. [PMID: 17465404 DOI: 10.1002/asia.200700025] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A new bioinspired nanomaterial has been obtained by chemisorption of folic acid onto nanocrystalline titanium dioxide. The organic chromophore is linked with the semiconductor surface via the glutamate chain and anchored with the carboxylate group. The geometry and electronic structure of the chromophore was studied in detail with DFT. Photoelectrochemical studies revealed photosensitization of the new material towards visible light. The photoelectrodes composed of the folic acid/titanium dioxide hybrid material generated photocurrent over a 300-600-nm window. Moreover, the direction of the photocurrent could be changed from anodic to cathodic and vice versa by application of the appropriate photoelectrode potential. Photoelectrochemical and spectroscopic studies allowed the elucidation of the mechanism of photocurrent switching. Photoelectrodes composed of folate-modified titanium dioxide may serve as a simple model of optoelectronic switches and may constitute the basis for molecular photoelectronic devices.
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Affiliation(s)
- Sylwia Gaweda
- Centrum Nanochemii Nieorganicznej, Wydział Chemii, Uniwersytet Jagielloński ul. Romana Ingardena 3, 30-060 Kraków, Poland
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90
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Cabrerizo FM, Lorente C, Vignonl M, Cabrerizo R, Thomas AH, Capparelli AL. Photochemical Behavior of 6-Methylpterin in Aqueous Solutions: Generation of Reactive Oxygen Species¶. Photochem Photobiol 2007. [DOI: 10.1111/j.1751-1097.2005.tb01445.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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91
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Steindal AH, Juzeniene A, Johnsson A, Moan J. Photodegradation of 5-methyltetrahydrofolate: biophysical aspects. Photochem Photobiol 2007; 82:1651-5. [PMID: 16879038 DOI: 10.1562/2006-06-09-ra-915] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
5-methyltetrahydrofolate (5MTHF) absorbs UV radiation and has an absorption coefficient of 24250+/-1170 M(-1) cm(-1) at 290 nm. It has a weak fluorescence emission in the wavelength region around 360 nm. Our data demonstrated induction of 5-methyldihydrofolate by exposure to UVB and, after continues irradiation, p-aminobenzoyl-L-glutamic acid was found. The photodegradation of 5MTHF follows a first order kinetic with a degradation rate constant of 9.2 x 10(-3) min(-1) under our conditions (fluence rate of 2.15 mW cm(-2), exposure wavelengths from 280 to 350 nm). Our results indicate that a direct degradation of 5MTHF by UV exposure in humans in vivo is rather unlikely. 5MTHF mainly absorbs, and is degraded by, UVB and UVC, radiation that does not penetrate the earth's atmosphere and the human skin well.
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Affiliation(s)
- Arnfinn Hykkerud Steindal
- Department of Radiation Biology, Institute for Cancer Research, The Norwegian Radium Hospital, Montebello, N-0310 Oslo, Norway.
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92
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Song QH, Hwang KC. Direct observation for photophysical and photochemical processes of folic acid in DMSO solution. J Photochem Photobiol A Chem 2007. [DOI: 10.1016/j.jphotochem.2006.05.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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93
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Steindal AH, Juzeniene A, Johnsson A, Moan J. Photodegradation of 5-methyltetrahydrofolate: Biophysical Aspects. Photochem Photobiol 2006. [DOI: 10.1111/j.1751-1097.2006.tb09826.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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94
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Hirakawa K. Fluorometry of hydrogen peroxide using oxidative decomposition of folic acid. Anal Bioanal Chem 2006; 386:244-8. [PMID: 16896621 DOI: 10.1007/s00216-006-0649-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2006] [Revised: 06/19/2006] [Accepted: 06/23/2006] [Indexed: 10/24/2022]
Abstract
Hydrogen peroxide (H2O2) is one of the most important reactive oxygen species. In the present study, a fluorometry method for detecting H2O2 utilizing folic acid was evaluated. Folic acid was decomposed by H2O2 in the presence of Cu(II) into pterine-6-carboxylic acid, leading to strong fluorescence enhancement. In the absence of the metal ion, superoxide and H2O2 could not decompose folic acid. Also, H2O2 plus sodium hypochlorite (a source of singlet oxygen) could not induce fluorescence enhancement. These results demonstrate that H2O2 can be selectively detected using folic acid plus Cu(II). The limit of detection (LOD; at S/N=3) for H2O2 is 0.5 microM. This method based on the fluorescence enhancement of folic acid was applied in order to determine small amounts of H2O2 generated through the autooxidation of semicarbazide (generation rate: approximately 0.01 microM min(-1)), a carcinogenic compound.
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Affiliation(s)
- Kazutaka Hirakawa
- Department of Basic Engineering (Chemistry), Faculty of Engineering, Shizuoka University, Johoku 3-5-1, Hamamatsu, Shizuoka 432-8561, Japan.
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95
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Thomas A, Cabrerizo R, Vignoni M, Erra-Balsells R, Cabrerizo F, Capparelli A. Photoinduced Formation of Reactive Oxygen Species from the Acid Form of 6-(Hydroxymethyl)pterin in Aqueous Solution. Helv Chim Acta 2006. [DOI: 10.1002/hlca.200690107] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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96
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Abstract
Pterins belong to a family of heterocyclic compounds present in a wide range of living systems and participate in relevant biological functions. Interest in the photochemistry and photophysics of this group of compounds has increased since the participation of pterin derivatives in different photobiological processes has been suggested or demonstrated in recent decades. This account describes and connects basic studies on the fluorescence emission, the photooxidation, and the photosensitizing properties of oxidized six-substituted pterins in aqueous solution under UV-A irradiation. The biological implications of these studies are also discussed.
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Affiliation(s)
- Carolina Lorente
- Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), Facultad de Ciencias Exactas, Universidad Nacional de La Plata (UNLP), CONICET, Casilla de Correo 16, Sucursal 4 (1900), La Plata, Argentina
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Vorobey P, Steindal AE, Off MK, Vorobey A, Moan J. Influence of Human Serum Albumin on Photodegradation of Folic Acid in Solution. Photochem Photobiol 2006; 82:817-22. [PMID: 16454580 DOI: 10.1562/2005-11-23-ra-739] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
It has been proposed that photodegradation of folates may be the reason for the pigmentation of races living under high fluence rates of ultraviolet radiation. The photodegradation of folic acid (FA) induced by ultraviolet-A (UV-A) radiation, in solution and in the presence of human serum albumin (HSA), was studied with absorption and fluorescence spectroscopy. FA photodegradation, with formation of p-aminobenzoyl-l-glutamic acid, 6-formylpterin and pterin-6-carboxylic acid, was found to follow an exponential trend. A scheme of FA photodegradation, which involves photosensitization of FA degradation by its photoproducts, was proposed. The rate of FA photodegradation decreased drastically in the presence of HSA, whereas the spectral characteristics of the photoproducts remained constant. The reduction of the FA photodegradation rate by HSA was accompanied by degradation of tryptophan in HSA. Tryptophan, when added to solutions of FA, had a similar effect as HSA. In solutions of FA and HSA the FA photoproducts cause photodamage mainly to HSA rather than to FA itself. The oxygen dependence of FA photodegradation and the inhibition of this process by sodium azide indicate that singlet oxygen may participate in the photosensitizing activity of FA photoproducts.
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Affiliation(s)
- Pavel Vorobey
- Department of Radiation Biology, Institute for Cancer Research, The Norwegian Radium Hospital, Oslo, Norway
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98
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Yamada H, Arai T, Endo N, Yamashita K, Nonogawa M, Makino K, Fukuda K, Sasada M, Uchiyama T. Photodynamic effects of a novel pterin derivative on a pancreatic cancer cell line. Biochem Biophys Res Commun 2005; 333:763-7. [PMID: 15964552 DOI: 10.1016/j.bbrc.2005.05.185] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2005] [Accepted: 05/18/2005] [Indexed: 11/22/2022]
Abstract
6-Formylpterin (6FP) has the potential to produce singlet oxygen (1O2) under UV-A radiation. In order to apply this potential to anti-cancer photodynamic therapy (PDT), we prepared a novel variant of 6FP, 2-(N,N-dimethylaminomethyleneamino)-6-formyl-3-pivaloylpteridine-4-one (6FP-tBu-DMF), and examined its photodynamic effects on a pancreatic cancer cell line, Panc-1 cells. The study using laser scanning confocal microscopy showed that the drug uptake, the 1O2 generation, and cell death were observed in the 6FP-tBu-DMF-treated cells, while these phenomena were not observed in the 6FP-treated cells. The MTT assay also showed the decrease in cell viability only in the 6FP-tBu-DMF-treated cells. Since 6FP and 6FP-tBu-DMF generate 1O2 to the same extent under UV-A radiation in aqueous solutions, these results indicated that the differences in the photodynamic effects between 6FP and 6FP-tBu-DMF were entirely attributed to the differences in the cell permeability between them. The development of cell permeable pterin derivatives has the potential for application in PDT.
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Affiliation(s)
- Hiroko Yamada
- Department of Hematology and Oncology, Kyoto University Hospital, Kyoto 606-8507, Japan
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99
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Telegina TA, Lyudnikova TA, Zemskova YL, Sviridov EA, Kritsky MS. Resistance of 5,10-methenyltetrahydrofolate to ultraviolet radiation. APPL BIOCHEM MICRO+ 2005. [DOI: 10.1007/s10438-005-0047-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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100
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Off MK, Steindal AE, Porojnicu AC, Juzeniene A, Vorobey A, Johnsson A, Moan J. Ultraviolet photodegradation of folic acid. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2005; 80:47-55. [PMID: 15963436 DOI: 10.1016/j.jphotobiol.2005.03.001] [Citation(s) in RCA: 159] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 01/28/2005] [Revised: 03/07/2005] [Accepted: 03/15/2005] [Indexed: 11/20/2022]
Abstract
The vitamin folate is vital for all living creatures. Scientists have suggested that ultraviolet degradation of folate in vivo played a role in the evolution of mankind. In order to better understand the photodegradation of folate, we have provided a spectroscopic study of the ultraviolet photodegradation of aqueous folic acid under aerobic conditions. We found strong indications that the folic acid molecule is cleaved into p-aminobenzoyl-L-glutamic acid and 6-formyl pterin when exposed to ultraviolet radiation. When the irradiation continues, 6-formyl pterin is degraded to pterin-6-carboxylic acid. The photodegradation of folic acid is divided into three phases. In the first phase, the formation of photoproducts follows a zero order rate law. In the second phase the presence of photoproducts sensitizes the degradation of folic acid and the degradation process is accelerated. In the third phase the degradation of 6-formyl pterin to pterin-6-carboxylic acid is the dominating process. This reaction follows a first order rate law. We show that both 6-formyl pterin and pterin-6-carboxylic acid sensitize the photodegradation of folic acid. However, experiments performed in heavy water indicate that generation of singlet oxygen is probably not the explanation for the photosensitizing of folic acid.
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Affiliation(s)
- Morten Kristian Off
- Department of Radiation Biology, Institute for Cancer Research, The Norwegian Radium Hospital, Montebello, Oslo.
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