W. H. Koppenol - Profile on Academia.edu (original) (raw)
Papers by W. H. Koppenol
The Journal of Physical Chemistry, 1984
For the standard reduction potential of the hydroxyl radical/hydroxide couple, two values are fou... more For the standard reduction potential of the hydroxyl radical/hydroxide couple, two values are found in the literature, 2.0 and 1.4 V. Thermochemical data yield 1.98 V for EO(.OH,/OH-,,). Hydration of the hydroxyl radical by -5 kcal/mol changes this value to 1.77 V for Eo'(.OH,,/OH-,,), which is still considerably higher than 1.4 V. It is concluded that the latter value is incorrect. The following thermodynamic quantities are derived from, or consistent with, the new Eo' value:
Reaction of peroxynitrite with L-tryptophan
Redox Report, 1996
ABSTRACT
ChemInform Abstract: Reactions of Fe(II)nta and Fe(II)edda with Hydrogen Peroxide
ChemInform, 1988
Cytochrome c Mobility in the Eukaryotic Electron Transport Chain
Electron Transport and Oxygen Utilization, 1982
[18] Nitration and hydroxylation of phenolic compounds by peroxynitrite
Methods in Enzymology, 1996
Pure and Applied Chemistry, 2001
Republication or reproduction of this report or its storage and/or dissemination by electronic me... more Republication or reproduction of this report or its storage and/or dissemination by electronic means is permitted without the need for formal IUPAC permission on condition that an acknowledgment, with full reference to the source along with use of the copyright symbol ©, the name IUPAC, and the year of publication, are prominently visible. Publication of a translation into another language is subject to the additional condition of prior approval from the relevant IUPAC National Adhering Organization.
The Journal of Physical Chemistry, 1989
maximum activity at optimal wo values ranging from 10 to 15. At the same time, adjusting a revers... more maximum activity at optimal wo values ranging from 10 to 15. At the same time, adjusting a reversed micellar solution of high wo to the optimal range by adding surfactant may not improve catalytic efficiency due to adverse proteinsurfactant interactions.% The ability to adjust wo through hydrate formation (keeping surfactant concentration constant) may thus have implications to the design of protein-containing reversed micellar systems.
Methods in enzymology, 1990
The Fenton reaction, or the reaction of ferrous ion with hydrogen peroxide at low pH, is generall... more The Fenton reaction, or the reaction of ferrous ion with hydrogen peroxide at low pH, is generally considered to yield the hydroxyl radical. This radical is a strong oxidizing agent [E°( • OH/H20) = 2.73 V] 1 and attacks various small molecules with rates of 108-101° M -~ sec -1, whereas its reaction with proteins is diffusion controUed. 2 The products are carbon-centered radicals that in the presence of oxygen are converted to organic hydroperoxyl radicals) These radicals are rather oxidizing and can start various chain reactions. 4 The propagation reactions are well understood and are responsible for far more damage than the initiating event. It is clear that oxygen plays a dual role in this process: it makes the formation of the oxidizing species possible in the first place, and, second, it amplifies the damage through the chain reactions.
Metal ions in biological systems, 1999
Oxyradicals play a role in several diseases. While for several decades the hydroxyl radical -prod... more Oxyradicals play a role in several diseases. While for several decades the hydroxyl radical -produced via the Fenton reaction -has been considered the species that initiates oxyradical damage, new findings suggest that much of this damage can be ascribed to peroxynitrite, O=NOO -, formed from the reaction of the superoxide anion with nitrogen monoxide near activated macrophages. The rate constant for the reaction of this reaction has been investigated by flash photolysis and was found to be significantly higher than previously described in the literature, 1.9 x 10 10 M -1 s -1 . Studies of the isomerization to nitrate resulted in the discovery of a complex between peroxynitrite and its protonated form with a stability constant of 1 x 10 4 M -1 . Some of the harmful reaction of peroxynitrous acid have been ascribed to the hydroxyl radical as a product of homolysis of the O-O bond during the conversion to nitrate. Kinetics of the isomerization reaction as a function of pressure show that the activation volume is only +1.5+1.0 ml mol -1 , which is inconsistent with homolysis. Instead, an intermediate, possibly a distorted trans-isomer of O=NOOH could be responsible for the harmful reactions of peroxynitrite.
Peroxynitrite studied by stopped-flow spectroscopy
Methods in enzymology, 1999
... a rate constant of 3 10 4 M 1 sec - i to form, presumably, the species ONOOCO2 .43 They estim... more ... a rate constant of 3 10 4 M 1 sec - i to form, presumably, the species ONOOCO2 .43 They estimated the lifetime of the adduct (systematic substitutive name: 1-carboxylato-2-nitrosodioxi-dane) to be ... 53 p. Di Mascio, EJH Bechara, MHG Medeiros, K. Briviba, and H. Sies, FEBS Lett ...
Syntheses of peroxynitrite: to go with the flow or on solid grounds?
Methods in enzymology, 1996
... Titre du document / Document title. SYNTHESES OF PEROXYNITRITE : TO GO WITH THE FLOW OR ON SO... more ... Titre du document / Document title. SYNTHESES OF PEROXYNITRITE : TO GO WITH THE FLOW OR ON SOLID GROUNDS ? Auteur(s) / Author(s). KOPPENOL WH ; KISSNER R. ; BECKMAN JS ; Revue / Journal Title. Methods in enzymology ISSN 0076-6879 CODEN MENZAU ...
Thermodynamics of reactions involving nitrogen-oxygen compounds
Methods in enzymology, 1996
Say NO to nitric oxide: nomenclature for nitrogen- and oxygen-containing compounds
Methods in enzymology, 1996
Superoxide dismutase and oxygen toxicity
Bulletin européen de physiopathologie respiratoire, 1981
ABSTRACT
Kinetics and mechanism of the reduction of ferricytochrome c by the superoxide anion
The Journal of biological chemistry, Jan 25, 1982
The temperature and pH dependence of the reaction of the superoxide radical anion with ferricytoc... more The temperature and pH dependence of the reaction of the superoxide radical anion with ferricytochrome c have been measured using the pulse-radiolysis technique. The temperature dependence of the reaction at low ionic strength yields an activation energy of 31 +/- 5 kJ/mol as compared to 14 +/- 3 kJ/mol for the reaction of CO2.(-) under the same conditions. The pH dependence fits the single pK'a of ferricytochrome c of 9.1. The bimolecular rate constant for the reaction of the superoxide anion with ferricytochrome c at pH 7.8, 21 +/- 2 degrees C, in the presence of 50 mM phosphate and 0.1 mM EDTA is (2.6 +/- 0.1) X 10(5) M-1 s-1. Using this value, 1 unit of superoxide dismutase activity (McCord, J. M., and Fridovich, I. (1969) J. Biol. Chem. 244, 6049-6055) is calculated to be 3.6 +/- 0.3 pmol of enzyme if the assay is performed in a total volume of 3.0 ml. Copper ions reduce the yield of the reaction of ferricytochrome c with CO2.(-). The reactivities of native and singly modif...
The Journal of Physical Chemistry, 1987
The Journal of biological chemistry, Jan 25, 1982
The electric potential field around native horse cytochrome c and 12 singly modified 4-carboxy-2,... more The electric potential field around native horse cytochrome c and 12 singly modified 4-carboxy-2,4-dinitrophenyl- (CDNP) lysine cytochromes c is asymmetric, mainly because of the inhomogeneous distribution of negative charges. Dipole moments of 325 and 308 debye, (1.08.10(-27) and 1.03.10(-27) coulomb.meter), respectively, were calculated for horse ferri- and ferrocytochrome c. The angle between the heme plane and the dipole vector of horse ferricytochrome c is 33 degrees and increases 1 degree upon reduction to the ferrous form. Dipole moments of the CDNP-lysine cytochromes c differ from that of native cytochrome c by as much as 140 debye in magnitude and 45 degrees in direction. It is proposed that its dipole moment causes cytochrome c to orient itself in the electric fields of its redox partners, and that the CDNP-lysine cytochromes c, which have different dipole moments, do not form a productive complex. Reorientation to the correct position for electron transfer increases the a...
The Journal of biological chemistry, Jan 25, 1981
1. Optimal activity for the enzymic reduction of horse cytochrome c by beef sulfite oxidase was o... more 1. Optimal activity for the enzymic reduction of horse cytochrome c by beef sulfite oxidase was observed at pH 8.0.
The Journal of biological chemistry, Jan 25, 1980
The stability of the native conformation of the heme crevice of ferricytochrome c, as assessed by... more The stability of the native conformation of the heme crevice of ferricytochrome c, as assessed by the p& and transition temperature (tip) values for the 695 nm absorption band, varies considerably among native and singly modified proteins of mammalian species. The pK, values are about 9.5 for the ape and Old World monkey cytochromes, 8.7 for the New World monkey proteins, 9.1 for those of prosimians and non-primate mammals such as the horse and beef, and 8.1 for the carboxydinitrophenyl-and trinitrophenyl-lysine 13 derivatives of horse cytochrome c. The t l / z values follow the same pattern over the range of 42-55°C. From comparisons of these relative stabilities and the corresponding amino acid sequence changes, it was concluded that two interactions on the surface of the molecule are important in maintaining the closed structure of the heme crevice. One of these is a salt bridge between the eamino of lysyl residue 13 and the y-carboxyl of glutamyl residue 90, constituting the top heme crevice bond. The other is a hydrogen bond between the Eamino of lysyl residue 79 and the backbone carbonyl of residue 47, either a serine or a threonine, constituting the bottom heme crevice bond. The stability of the closed form of the heme crevice is modulated by the nature of residue 50, which when acidic, lowers the proportion of molecules with an intact bottom bond by competing with residue 47 for the €-amino of lysine 79. Anions, such as phosphate and citrate, which bind with high affinity to a site not far from the top heme crevice bond increase the p~9 5 n m at relatively low concentrations, while other anions which do not interact with this site are effective only at much higher ionic strengths.
Distance-Dependent Diffusion-Controlled Reaction of • NO and O 2 •− at Chemical Equilibrium with ONOO −
The Journal of Physical Chemistry B, 2010
The fast reaction of (•)NO and O(2)(•-) to give ONOO(-) has been extensively studied at irreversi... more The fast reaction of (•)NO and O(2)(•-) to give ONOO(-) has been extensively studied at irreversible conditions, but the reasons for the wide variations in observed forward rate constants (3.8 ≤ k(f) ≤ 20 × 10(9) M(-1) s(-1)) remain unexplained. We characterized the diffusion-dependent aqueous (pH > 12) chemical equilibrium of the form (•)NO + O(2)(•-) = ONOO(-) with respect to its dependence on temperature, viscosity, and [ONOO(-)](eq) by determining [ONOO(-)](eq) and [(•)NO](eq). The equilibrium forward reaction rate constant (k(f)(eq)) has negative activation energy, in contrast to that found under irreversible conditions. In contradiction to the law of mass action, we demonstrate that the equilibrium constant depends on ONOO(-) concentration. Therefore, a wide range of k(f)(eq) values could be derived (7.5-21 × 10(9) M(-1) s(-1)). Of general interest, the variations in k(f) can thus be explained by its dependence on the distance between ONOO(-) particles (sites of generation of (•)NO and O(2)(•-)).
The Journal of Physical Chemistry, 1984
For the standard reduction potential of the hydroxyl radical/hydroxide couple, two values are fou... more For the standard reduction potential of the hydroxyl radical/hydroxide couple, two values are found in the literature, 2.0 and 1.4 V. Thermochemical data yield 1.98 V for EO(.OH,/OH-,,). Hydration of the hydroxyl radical by -5 kcal/mol changes this value to 1.77 V for Eo'(.OH,,/OH-,,), which is still considerably higher than 1.4 V. It is concluded that the latter value is incorrect. The following thermodynamic quantities are derived from, or consistent with, the new Eo' value:
Reaction of peroxynitrite with L-tryptophan
Redox Report, 1996
ABSTRACT
ChemInform Abstract: Reactions of Fe(II)nta and Fe(II)edda with Hydrogen Peroxide
ChemInform, 1988
Cytochrome c Mobility in the Eukaryotic Electron Transport Chain
Electron Transport and Oxygen Utilization, 1982
[18] Nitration and hydroxylation of phenolic compounds by peroxynitrite
Methods in Enzymology, 1996
Pure and Applied Chemistry, 2001
Republication or reproduction of this report or its storage and/or dissemination by electronic me... more Republication or reproduction of this report or its storage and/or dissemination by electronic means is permitted without the need for formal IUPAC permission on condition that an acknowledgment, with full reference to the source along with use of the copyright symbol ©, the name IUPAC, and the year of publication, are prominently visible. Publication of a translation into another language is subject to the additional condition of prior approval from the relevant IUPAC National Adhering Organization.
The Journal of Physical Chemistry, 1989
maximum activity at optimal wo values ranging from 10 to 15. At the same time, adjusting a revers... more maximum activity at optimal wo values ranging from 10 to 15. At the same time, adjusting a reversed micellar solution of high wo to the optimal range by adding surfactant may not improve catalytic efficiency due to adverse proteinsurfactant interactions.% The ability to adjust wo through hydrate formation (keeping surfactant concentration constant) may thus have implications to the design of protein-containing reversed micellar systems.
Methods in enzymology, 1990
The Fenton reaction, or the reaction of ferrous ion with hydrogen peroxide at low pH, is generall... more The Fenton reaction, or the reaction of ferrous ion with hydrogen peroxide at low pH, is generally considered to yield the hydroxyl radical. This radical is a strong oxidizing agent [E°( • OH/H20) = 2.73 V] 1 and attacks various small molecules with rates of 108-101° M -~ sec -1, whereas its reaction with proteins is diffusion controUed. 2 The products are carbon-centered radicals that in the presence of oxygen are converted to organic hydroperoxyl radicals) These radicals are rather oxidizing and can start various chain reactions. 4 The propagation reactions are well understood and are responsible for far more damage than the initiating event. It is clear that oxygen plays a dual role in this process: it makes the formation of the oxidizing species possible in the first place, and, second, it amplifies the damage through the chain reactions.
Metal ions in biological systems, 1999
Oxyradicals play a role in several diseases. While for several decades the hydroxyl radical -prod... more Oxyradicals play a role in several diseases. While for several decades the hydroxyl radical -produced via the Fenton reaction -has been considered the species that initiates oxyradical damage, new findings suggest that much of this damage can be ascribed to peroxynitrite, O=NOO -, formed from the reaction of the superoxide anion with nitrogen monoxide near activated macrophages. The rate constant for the reaction of this reaction has been investigated by flash photolysis and was found to be significantly higher than previously described in the literature, 1.9 x 10 10 M -1 s -1 . Studies of the isomerization to nitrate resulted in the discovery of a complex between peroxynitrite and its protonated form with a stability constant of 1 x 10 4 M -1 . Some of the harmful reaction of peroxynitrous acid have been ascribed to the hydroxyl radical as a product of homolysis of the O-O bond during the conversion to nitrate. Kinetics of the isomerization reaction as a function of pressure show that the activation volume is only +1.5+1.0 ml mol -1 , which is inconsistent with homolysis. Instead, an intermediate, possibly a distorted trans-isomer of O=NOOH could be responsible for the harmful reactions of peroxynitrite.
Peroxynitrite studied by stopped-flow spectroscopy
Methods in enzymology, 1999
... a rate constant of 3 10 4 M 1 sec - i to form, presumably, the species ONOOCO2 .43 They estim... more ... a rate constant of 3 10 4 M 1 sec - i to form, presumably, the species ONOOCO2 .43 They estimated the lifetime of the adduct (systematic substitutive name: 1-carboxylato-2-nitrosodioxi-dane) to be ... 53 p. Di Mascio, EJH Bechara, MHG Medeiros, K. Briviba, and H. Sies, FEBS Lett ...
Syntheses of peroxynitrite: to go with the flow or on solid grounds?
Methods in enzymology, 1996
... Titre du document / Document title. SYNTHESES OF PEROXYNITRITE : TO GO WITH THE FLOW OR ON SO... more ... Titre du document / Document title. SYNTHESES OF PEROXYNITRITE : TO GO WITH THE FLOW OR ON SOLID GROUNDS ? Auteur(s) / Author(s). KOPPENOL WH ; KISSNER R. ; BECKMAN JS ; Revue / Journal Title. Methods in enzymology ISSN 0076-6879 CODEN MENZAU ...
Thermodynamics of reactions involving nitrogen-oxygen compounds
Methods in enzymology, 1996
Say NO to nitric oxide: nomenclature for nitrogen- and oxygen-containing compounds
Methods in enzymology, 1996
Superoxide dismutase and oxygen toxicity
Bulletin européen de physiopathologie respiratoire, 1981
ABSTRACT
Kinetics and mechanism of the reduction of ferricytochrome c by the superoxide anion
The Journal of biological chemistry, Jan 25, 1982
The temperature and pH dependence of the reaction of the superoxide radical anion with ferricytoc... more The temperature and pH dependence of the reaction of the superoxide radical anion with ferricytochrome c have been measured using the pulse-radiolysis technique. The temperature dependence of the reaction at low ionic strength yields an activation energy of 31 +/- 5 kJ/mol as compared to 14 +/- 3 kJ/mol for the reaction of CO2.(-) under the same conditions. The pH dependence fits the single pK'a of ferricytochrome c of 9.1. The bimolecular rate constant for the reaction of the superoxide anion with ferricytochrome c at pH 7.8, 21 +/- 2 degrees C, in the presence of 50 mM phosphate and 0.1 mM EDTA is (2.6 +/- 0.1) X 10(5) M-1 s-1. Using this value, 1 unit of superoxide dismutase activity (McCord, J. M., and Fridovich, I. (1969) J. Biol. Chem. 244, 6049-6055) is calculated to be 3.6 +/- 0.3 pmol of enzyme if the assay is performed in a total volume of 3.0 ml. Copper ions reduce the yield of the reaction of ferricytochrome c with CO2.(-). The reactivities of native and singly modif...
The Journal of Physical Chemistry, 1987
The Journal of biological chemistry, Jan 25, 1982
The electric potential field around native horse cytochrome c and 12 singly modified 4-carboxy-2,... more The electric potential field around native horse cytochrome c and 12 singly modified 4-carboxy-2,4-dinitrophenyl- (CDNP) lysine cytochromes c is asymmetric, mainly because of the inhomogeneous distribution of negative charges. Dipole moments of 325 and 308 debye, (1.08.10(-27) and 1.03.10(-27) coulomb.meter), respectively, were calculated for horse ferri- and ferrocytochrome c. The angle between the heme plane and the dipole vector of horse ferricytochrome c is 33 degrees and increases 1 degree upon reduction to the ferrous form. Dipole moments of the CDNP-lysine cytochromes c differ from that of native cytochrome c by as much as 140 debye in magnitude and 45 degrees in direction. It is proposed that its dipole moment causes cytochrome c to orient itself in the electric fields of its redox partners, and that the CDNP-lysine cytochromes c, which have different dipole moments, do not form a productive complex. Reorientation to the correct position for electron transfer increases the a...
The Journal of biological chemistry, Jan 25, 1981
1. Optimal activity for the enzymic reduction of horse cytochrome c by beef sulfite oxidase was o... more 1. Optimal activity for the enzymic reduction of horse cytochrome c by beef sulfite oxidase was observed at pH 8.0.
The Journal of biological chemistry, Jan 25, 1980
The stability of the native conformation of the heme crevice of ferricytochrome c, as assessed by... more The stability of the native conformation of the heme crevice of ferricytochrome c, as assessed by the p& and transition temperature (tip) values for the 695 nm absorption band, varies considerably among native and singly modified proteins of mammalian species. The pK, values are about 9.5 for the ape and Old World monkey cytochromes, 8.7 for the New World monkey proteins, 9.1 for those of prosimians and non-primate mammals such as the horse and beef, and 8.1 for the carboxydinitrophenyl-and trinitrophenyl-lysine 13 derivatives of horse cytochrome c. The t l / z values follow the same pattern over the range of 42-55°C. From comparisons of these relative stabilities and the corresponding amino acid sequence changes, it was concluded that two interactions on the surface of the molecule are important in maintaining the closed structure of the heme crevice. One of these is a salt bridge between the eamino of lysyl residue 13 and the y-carboxyl of glutamyl residue 90, constituting the top heme crevice bond. The other is a hydrogen bond between the Eamino of lysyl residue 79 and the backbone carbonyl of residue 47, either a serine or a threonine, constituting the bottom heme crevice bond. The stability of the closed form of the heme crevice is modulated by the nature of residue 50, which when acidic, lowers the proportion of molecules with an intact bottom bond by competing with residue 47 for the €-amino of lysine 79. Anions, such as phosphate and citrate, which bind with high affinity to a site not far from the top heme crevice bond increase the p~9 5 n m at relatively low concentrations, while other anions which do not interact with this site are effective only at much higher ionic strengths.
Distance-Dependent Diffusion-Controlled Reaction of • NO and O 2 •− at Chemical Equilibrium with ONOO −
The Journal of Physical Chemistry B, 2010
The fast reaction of (•)NO and O(2)(•-) to give ONOO(-) has been extensively studied at irreversi... more The fast reaction of (•)NO and O(2)(•-) to give ONOO(-) has been extensively studied at irreversible conditions, but the reasons for the wide variations in observed forward rate constants (3.8 ≤ k(f) ≤ 20 × 10(9) M(-1) s(-1)) remain unexplained. We characterized the diffusion-dependent aqueous (pH > 12) chemical equilibrium of the form (•)NO + O(2)(•-) = ONOO(-) with respect to its dependence on temperature, viscosity, and [ONOO(-)](eq) by determining [ONOO(-)](eq) and [(•)NO](eq). The equilibrium forward reaction rate constant (k(f)(eq)) has negative activation energy, in contrast to that found under irreversible conditions. In contradiction to the law of mass action, we demonstrate that the equilibrium constant depends on ONOO(-) concentration. Therefore, a wide range of k(f)(eq) values could be derived (7.5-21 × 10(9) M(-1) s(-1)). Of general interest, the variations in k(f) can thus be explained by its dependence on the distance between ONOO(-) particles (sites of generation of (•)NO and O(2)(•-)).