Producción CyT
Artículo
Autoría
Andrés H. Thomas
;
LORENTE, CAROLINA
;
Alberto L. Capparelli
;
Meg R. Pokhrel
;
André M. Braun
;
Esther Oliveros
Fecha
2002
Editorial y Lugar de Edición
ROYAL SOC CHEMISTRY
Revista
Photochemical and Photobiological Sciences,
vol. 1
(pp. 421-426)
ROYAL SOC CHEMISTRY
Resumen
Información suministrada por el agente en
SIGEVA
Steady-state and time-resolved studies have been performed on four compounds of the pterin family (pterin, 6-carboxypterin, 6-formylpterin and folic acid) in aqueous solution, using the single photon counting technique. The fluorescence characteristics (spectra, quantum yields, lifetimes) of these compounds and their dependence on the pH have been investigated. Most pterins can exist in two acid¨Cbase forms over the pH range between 3 and 13. Emission spectra and excitation spectra were obt...
Steady-state and time-resolved studies have been performed on four compounds of the pterin family (pterin, 6-carboxypterin, 6-formylpterin and folic acid) in aqueous solution, using the single photon counting technique. The fluorescence characteristics (spectra, quantum yields, lifetimes) of these compounds and their dependence on the pH have been investigated. Most pterins can exist in two acid¨Cbase forms over the pH range between 3 and 13. Emission spectra and excitation spectra were obtained for both forms of each compound studied. Fluorescence quantum yields (¦µF) in acidic and basic media were measured. The ¦µF of folic acid (<0.005 in both media) is very low compared to those of pterin (0.27 in basic media and 0.33 in acidic media), 6-carboxypterin (0.18 in basic media and 0.28 in acidic media) and 6-formylpterin (0.07 in basic media and 0.12 in acidic media). The variation in integrated fluorescence intensity and fluorescence lifetimes (¦ÓF) was analysed as a function of pH. Dynamic quenching by OH was observed and the corresponding bimolecular rate constants for quenching of fluorescence (kq) were calculated. The reported values for kq (M1 s1) are 3.6 ¡Á 109, 1.9 ¡Á 109and 1.1 ¡Á 1010 M1 s1 for pterin, 6-carboxypterin and 6-formylpterin, respectively. respectively. values for kq (M1 s1) are 3.6 ¡Á 109, 1.9 ¡Á 109and 1.1 ¡Á 1010 M1 s1 for pterin, 6-carboxypterin and 6-formylpterin, respectively. respectively. and the corresponding bimolecular rate constants for quenching of fluorescence (kq) were calculated. The reported values for kq (M1 s1) are 3.6 ¡Á 109, 1.9 ¡Á 109and 1.1 ¡Á 1010 M1 s1 for pterin, 6-carboxypterin and 6-formylpterin, respectively. respectively. values for kq (M1 s1) are 3.6 ¡Á 109, 1.9 ¡Á 109and 1.1 ¡Á 1010 M1 s1 for pterin, 6-carboxypterin and 6-formylpterin, respectively. respectively. intensity and fluorescence lifetimes (¦ÓF) was analysed as a function of pH. Dynamic quenching by OH was observed and the corresponding bimolecular rate constants for quenching of fluorescence (kq) were calculated. The reported values for kq (M1 s1) are 3.6 ¡Á 109, 1.9 ¡Á 109and 1.1 ¡Á 1010 M1 s1 for pterin, 6-carboxypterin and 6-formylpterin, respectively. respectively. values for kq (M1 s1) are 3.6 ¡Á 109, 1.9 ¡Á 109and 1.1 ¡Á 1010 M1 s1 for pterin, 6-carboxypterin and 6-formylpterin, respectively. respectively. and the corresponding bimolecular rate constants for quenching of fluorescence (kq) were calculated. The reported values for kq (M1 s1) are 3.6 ¡Á 109, 1.9 ¡Á 109and 1.1 ¡Á 1010 M1 s1 for pterin, 6-carboxypterin and 6-formylpterin, respectively. respectively. values for kq (M1 s1) are 3.6 ¡Á 109, 1.9 ¡Á 109and 1.1 ¡Á 1010 M1 s1 for pterin, 6-carboxypterin and 6-formylpterin, respectively. respectively. those of pterin (0.27 in basic media and 0.33 in acidic media), 6-carboxypterin (0.18 in basic media and 0.28 in acidic media) and 6-formylpterin (0.07 in basic media and 0.12 in acidic media). The variation in integrated fluorescence intensity and fluorescence lifetimes (¦ÓF) was analysed as a function of pH. Dynamic quenching by OH was observed and the corresponding bimolecular rate constants for quenching of fluorescence (kq) were calculated. The reported values for kq (M1 s1) are 3.6 ¡Á 109, 1.9 ¡Á 109and 1.1 ¡Á 1010 M1 s1 for pterin, 6-carboxypterin and 6-formylpterin, respectively. respectively. values for kq (M1 s1) are 3.6 ¡Á 109, 1.9 ¡Á 109and 1.1 ¡Á 1010 M1 s1 for pterin, 6-carboxypterin and 6-formylpterin, respectively. respectively. and the corresponding bimolecular rate constants for quenching of fluorescence (kq) were calculated. The reported values for kq (M1 s1) are 3.6 ¡Á 109, 1.9 ¡Á 109and 1.1 ¡Á 1010 M1 s1 for pterin, 6-carboxypterin and 6-formylpterin, respectively. respectively. values for kq (M1 s1) are 3.6 ¡Á 109, 1.9 ¡Á 109and 1.1 ¡Á 1010 M1 s1 for pterin, 6-carboxypterin and 6-formylpterin, respectively. respectively. intensity and fluorescence lifetimes (¦ÓF) was analysed as a function of pH. Dynamic quenching by OH was observed and the corresponding bimolecular rate constants for quenching of fluorescence (kq) were calculated. The reported values for kq (M1 s1) are 3.6 ¡Á 109, 1.9 ¡Á 109and 1.1 ¡Á 1010 M1 s1 for pterin, 6-carboxypterin and 6-formylpterin, respectively. respectively. values for kq (M1 s1) are 3.6 ¡Á 109, 1.9 ¡Á 109and 1.1 ¡Á 1010 M1 s1 for pterin, 6-carboxypterin and 6-formylpterin, respectively. respectively. and the corresponding bimolecular rate constants for quenching of fluorescence (kq) were calculated. The reported values for kq (M1 s1) are 3.6 ¡Á 109, 1.9 ¡Á 109and 1.1 ¡Á 1010 M1 s1 for pterin, 6-carboxypterin and 6-formylpterin, respectively. respectively. values for kq (M1 s1) are 3.6 ¡Á 109, 1.9 ¡Á 109and 1.1 ¡Á 1010 M1 s1 for pterin, 6-carboxypterin and 6-formylpterin, respectively. respectively. have been investigated. Most pterins can exist in two acid¨Cbase forms over the pH range between 3 and 13. Emission spectra and excitation spectra were obtained for both forms of each compound studied. Fluorescence quantum yields (¦µF) in acidic and basic media were measured. The ¦µF of folic acid (<0.005 in both media) is very low compared to those of pterin (0.27 in basic media and 0.33 in acidic media), 6-carboxypterin (0.18 in basic media and 0.28 in acidic media) and 6-formylpterin (0.07 in basic media and 0.12 in acidic media). The variation in integrated fluorescence intensity and fluorescence lifetimes (¦ÓF) was analysed as a function of pH. Dynamic quenching by OH was observed and the corresponding bimolecular rate constants for quenching of fluorescence (kq) were calculated. The reported values for kq (M1 s1) are 3.6 ¡Á 109, 1.9 ¡Á 109and 1.1 ¡Á 1010 M1 s1 for pterin, 6-carboxypterin and 6-formylpterin, respectively. respectively. values for kq (M1 s1) are 3.6 ¡Á 109, 1.9 ¡Á 109and 1.1 ¡Á 1010 M1 s1 for pterin, 6-carboxypterin and 6-formylpterin, respectively. respectively. and the corresponding bimolecular rate constants for quenching of fluorescence (kq) were calculated. The reported values for kq (M1 s1) are 3.6 ¡Á 109, 1.9 ¡Á 109and 1.1 ¡Á 1010 M1 s1 for pterin, 6-carboxypterin and 6-formylpterin, respectively. respectively. values for kq (M1 s1) are 3.6 ¡Á 109, 1.9 ¡Á 109and 1.1 ¡Á 1010 M1 s1 for pterin, 6-carboxypterin and 6-formylpterin, respectively. respectively. intensity and fluorescence lifetimes (¦ÓF) was analysed as a function of pH. Dynamic quenching by OH was observed and the corresponding bimolecular rate constants for quenching of fluorescence (kq) were calculated. The reported values for kq (M1 s1) are 3.6 ¡Á 109, 1.9 ¡Á 109and 1.1 ¡Á 1010 M1 s1 for pterin, 6-carboxypterin and 6-formylpterin, respectively. respectively. values for kq (M1 s1) are 3.6 ¡Á 109, 1.9 ¡Á 109and 1.1 ¡Á 1010 M1 s1 for pterin, 6-carboxypterin and 6-formylpterin, respectively. respectively. and the corresponding bimolecular rate constants for quenching of fluorescence (kq) were calculated. The reported values for kq (M1 s1) are 3.6 ¡Á 109, 1.9 ¡Á 109and 1.1 ¡Á 1010 M1 s1 for pterin, 6-carboxypterin and 6-formylpterin, respectively. respectively. values for kq (M1 s1) are 3.6 ¡Á 109, 1.9 ¡Á 109and 1.1 ¡Á 1010 M1 s1 for pterin, 6-carboxypterin and 6-formylpterin, respectively. respectively. those of pterin (0.27 in basic media and 0.33 in acidic media), 6-carboxypterin (0.18 in basic media and 0.28 in acidic media) and 6-formylpterin (0.07 in basic media and 0.12 in acidic media). The variation in integrated fluorescence intensity and fluorescence lifetimes (¦ÓF) was analysed as a function of pH. Dynamic quenching by OH was observed and the corresponding bimolecular rate constants for quenching of fluorescence (kq) were calculated. The reported values for kq (M1 s1) are 3.6 ¡Á 109, 1.9 ¡Á 109and 1.1 ¡Á 1010 M1 s1 for pterin, 6-carboxypterin and 6-formylpterin, respectively. respectively. values for kq (M1 s1) are 3.6 ¡Á 109, 1.9 ¡Á 109and 1.1 ¡Á 1010 M1 s1 for pterin, 6-carboxypterin and 6-formylpterin, respectively. respectively. and the corresponding bimolecular rate constants for quenching of fluorescence (kq) were calculated. The reported values for kq (M1 s1) are 3.6 ¡Á 109, 1.9 ¡Á 109and 1.1 ¡Á 1010 M1 s1 for pterin, 6-carboxypterin and 6-formylpterin, respectively. respectively. values for kq (M1 s1) are 3.6 ¡Á 109, 1.9 ¡Á 109and 1.1 ¡Á 1010 M1 s1 for pterin, 6-carboxypterin and 6-formylpterin, respectively. respectively. intensity and fluorescence lifetimes (¦ÓF) was analysed as a function of pH. Dynamic quenching by OH was observed and the corresponding bimolecular rate constants for quenching of fluorescence (kq) were calculated. The reported values for k
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PTERINSFLUORESCENCEPHOTOPHYSICS