... 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 ...
... 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 ...
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 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...
... 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 ...
... 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 ...
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 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...
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