Reaction of Peroxynitrite with Mn-Superoxide Dismutase (2001)

Manganese superoxide dismutase (Mn-SOD), a critical mitochondrial antioxidant enzyme, becomes inactivated and nitrated in vitro and potentially in vivo by peroxynitrite. Since peroxynitrite readily reacts with transition metal centers, we assessed the role of the manganese ion in the reaction between peroxynitrite and Mn-SOD. Peroxynitrite reacts with human recombinant and Escherichia coli Mn-SOD with a second order rate constant of 1.0 ± 0.2 × 105 and 1.4 ± 0.2 × 105m−1s−1 at pH 7.47 and 37 °C, respectively. TheE. coli apoenzyme, obtained by removing the manganese ion from the active site, presents a rate constant <104m−1 s−1for the reaction with peroxynitrite, whereas that of the manganese-reconstituted apoenzyme (apo/Mn) was comparable to that of the holoenzyme. Peroxynitrite-dependent nitration of 4-hydroxyphenylacetic acid was increased 21% by Mn-SOD. The apo/Mn also promoted nitration, but the apo and the zinc-substituted apoenzyme (apo/Zn) enzymes did not. The extent of tyrosine nitration in the enzyme was also affected by the presence and nature (i.e.manganese or zinc) of the metal center in the active site. For comparative purposes, we also studied the reaction of peroxynitrite with low molecular weight complexes of manganese and zinc with tetrakis-(4-benzoic acid) porphyrin (tbap). Mn(tbap) reacts with peroxynitrite with a rate constant of 6.8 ± 0.1 × 104m−1s−1 and maximally increases nitration yields by 350%. Zn(tbap), on the other hand, affords protection against nitration. Our results indicate that the manganese ion in Mn-SOD plays an important role in the decomposition kinetics of peroxynitrite and in peroxynitrite-dependent nitration of self and remote tyrosine residues. Manganese superoxide dismutase (Mn-SOD), a critical mitochondrial antioxidant enzyme, becomes inactivated and nitrated in vitro and potentially in vivo by peroxynitrite. Since peroxynitrite readily reacts with transition metal centers, we assessed the role of the manganese ion in the reaction between peroxynitrite and Mn-SOD. Peroxynitrite reacts with human recombinant and Escherichia coli Mn-SOD with a second order rate constant of 1.0 ± 0.2 × 105 and 1.4 ± 0.2 × 105m−1s−1 at pH 7.47 and 37 °C, respectively. TheE. coli apoenzyme, obtained by removing the manganese ion from the active site, presents a rate constant <104m−1 s−1for the reaction with peroxynitrite, whereas that of the manganese-reconstituted apoenzyme (apo/Mn) was comparable to that of the holoenzyme. Peroxynitrite-dependent nitration of 4-hydroxyphenylacetic acid was increased 21% by Mn-SOD. The apo/Mn also promoted nitration, but the apo and the zinc-substituted apoenzyme (apo/Zn) enzymes did not. The extent of tyrosine nitration in the enzyme was also affected by the presence and nature (i.e.manganese or zinc) of the metal center in the active site. For comparative purposes, we also studied the reaction of peroxynitrite with low molecular weight complexes of manganese and zinc with tetrakis-(4-benzoic acid) porphyrin (tbap). Mn(tbap) reacts with peroxynitrite with a rate constant of 6.8 ± 0.1 × 104m−1s−1 and maximally increases nitration yields by 350%. Zn(tbap), on the other hand, affords protection against nitration. Our results indicate that the manganese ion in Mn-SOD plays an important role in the decomposition kinetics of peroxynitrite and in peroxynitrite-dependent nitration of self and remote tyrosine residues. Manganese-superoxide dismutase (Mn-SOD) is the SOD isoform1found in the mitochondrial matrix of eukaryotes and in a variety of prokaryotes (1Weisiger R.A. Fridovich I. J. Biol. Chem. 1973; 248: 3582-3592Abstract Full Text PDF PubMed Google Scholar, 2Keele Jr., B.B. McCord J. Fridovich I. J. Biol. Chem. 1970; 245: 6176-6181Abstract Full Text PDF PubMed Google Scholar, 3Beyer W. Imlay J. Fridovich I. Prog. Nucleic Acids Res. Mol. Biol. 1991; 40: 221-253Crossref PubMed Scopus (341) Google Scholar). Mn-SODs from different organisms are homologous and have a manganese ion in the active site. Whereas the human mitochondrial enzyme is a homotetramer (∼88 kDa) (4Matsuda Y. Higashiyama S. Kijma Y. Suzuki Y. Kawano K. Akiyama M. Kawata S. Tarui S. Deutsch H.F. Taniguchi N. Eur. J. Biochem. 1990; 194: 713-720Crossref PubMed Scopus (57) Google Scholar), Escherichia coli Mn-SOD (45.8 kDa) is a dimer (3Beyer W. Imlay J. Fridovich I. Prog. Nucleic Acids Res. Mol. Biol. 1991; 40: 221-253Crossref PubMed Scopus (341) Google Scholar). Mitochondria are essential organelles where most of the cell superoxide (O⨪2) is produced (5Turrens J.F. Freeman B.A. Levitt J.G. Crapo J.D. Arch. Biochem. Biophys. 1982; 217: 401-410Crossref PubMed Scopus (353) Google Scholar, 6Boveris A. Methods Enzymol. 1984; 105: 429-435Crossref PubMed Scopus (417) Google Scholar), and therefore, Mn-SOD plays an active role detoxifying the cell from this species. In addition, pharmacological agents and cytokines that promote intracellular reactive oxygen species production, like paraquat (7Krall J. Bagley A.C. Mullenbach G.T. Hallewell R.A. Lynch R.E. J. Biol. Chem. 1988; 263: 1910-1914Abstract Full Text PDF PubMed Google Scholar) and tumor necrosis factor-α (8Liu R. Buettner G.R. Oberley L. Free Radic. Biol. Med. 2000; 28: 1197-1205Crossref PubMed Scopus (41) Google Scholar), induce Mn-SOD expression. Experiments with knock-out mice shed further light on the relevance of this enzyme, with Mn-SOD-deficient mice surviving only up to 3 weeks of age (9Lebovitz R.M. Zhang H. Vogel H. Cartwright Jr., J. Dionne L. Lu N. Huang S. Matzuk M.M. Proc. Natl. Acad. Sci. U. S. A. 1996; 93: 9782-9787Crossref PubMed Scopus (824) Google Scholar, 10Li Y. Huang T.-T. Carlson E.J. Melov S. Ursell P.C. Olson J.L. Noble L.J. Yoshimura M.P. Berger C. Chan P.H. Wallace D.C. Epstein C.J. Nat. Genet. 1995; 11: 376-381Crossref PubMed Scopus (1437) Google Scholar) and presenting many features of mitochondrial disease associated with reactive oxygen species toxicity (11Melov S. Coskun P. Patel M. Tuinstra R. Cottrell B. Jun A.S. Zastawny T.H. Dizdaroglu M. Goodman S.I. Huang T. Miziorko H. Epstein C.J. Wallace D.C. Proc. Natl. Acad. Sci. U. S. A. 1999; 96: 846-851Crossref PubMed Scopus (488) Google Scholar).Nitric oxide (NO⋅) is a relatively unreactive free radical formed by nitric oxide synthase (12Gross S.S. Wolin M.S. Annu. Rev. Physiol. 1995; 57: 737-769Crossref PubMed Scopus (820) Google Scholar). However, fast reaction of nitric oxide with superoxide gives rise to peroxynitrite anion (ONOO−), a potent oxidant (13Huie R.E. Padmaja S. Free Radic. Res. Commun. 1993; 18: 195-199Crossref PubMed Scopus (2006) Google Scholar, 14Goldstein S. Czapski G. Free Radic. Biol. Med. 1995; 19: 505-510Crossref PubMed Scopus (376) Google Scholar, 15Kissner R. Nauser T. Bugnonm P. Lyem P.G. Koppenol W.H. Chem. Res. Toxicol. 1997; 10: 1285-1292Crossref PubMed Scopus (560) Google Scholar). Peroxynitrite is formed during sepsis, inflammation, excitotoxicity, and ischemia-reperfusion of tissues, conditions under which the cellular production of nitric oxide and superoxide increase (12Gross S.S. Wolin M.S. Annu. Rev. Physiol. 1995; 57: 737-769Crossref PubMed Scopus (820) Google Scholar, 16Omar B. McCord J. Downey J. Sies H. Oxidative Stress: Oxidants and Antioxidants. Academic Press Inc, San Diego1991: 493-527Google Scholar, A. M. G. Sies H. Oxidative Oxidants and Antioxidants. Academic Press Inc, San Diego1991: Scholar, Huang M. J. 1999; 19: PubMed Google Scholar), and in with the of the presence of nitric oxide synthase in the P. C. 1997; PubMed Scopus Google Scholar, C. A. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar, A. C. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar), with the of nitric oxide J. and Scholar), the of peroxynitrite and the relevance of with peroxynitrite in but inactivated by peroxynitrite. nitration of tyrosine of human Mn-SOD results in enzyme in vitro PubMed Scopus Google Scholar, H. T. K. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar). The presence of a nitrated and enzyme in human Proc. Natl. Acad. Sci. U. S. A. 1996; Scopus Google Scholar) the relevance of this in Mn-SOD to tyrosine nitration, to an increase in peroxynitrite that in mitochondrial R. M. L. R. Arch. Biochem. Biophys. PubMed Scopus Google Scholar) and cell P. U. C. J. Biol. Chem. 1999; Full Text Full Text PDF Scopus Google decomposition is by a variety of R. A. B. G. H. L.J. Academic San Google Scholar). are like H. L. M. C. J. J. M. Arch. Biochem. Biophys. PubMed Scopus Google M.S. Padmaja S. Koppenol W.H. Chem. Res. Toxicol. 1996; PubMed Scopus Google Scholar), A. Freeman B. M. R. Arch. Biochem. Biophys. 1996; PubMed Scopus Google Scholar), and transition H. L. M. C. J. J. M. Arch. Biochem. Biophys. PubMed Scopus Google Scholar) that the of the and to the of species. In the of acid to radical and with yields up to R. A. B. G. H. L.J. Academic San Google Scholar, J. Freeman B.A. Proc. Natl. Acad. Sci. U. S. A. 1990; PubMed Scopus Google Scholar), in nitration yields in the of H. L. M. C. J. J. M. Arch. Biochem. Biophys. PubMed Scopus Google Scholar, M.S. Padmaja S. Koppenol W.H. Chem. Res. Toxicol. 1996; PubMed Scopus Google Scholar). In the of transition and SOD nitration yields are obtained H. L. M. C. J. J. M. Arch. Biochem. Biophys. PubMed Scopus Google Scholar, G. L. R. Chem. Res. Toxicol. 1997; 10: PubMed Scopus Google Scholar, G. I. I. Fridovich I. R. Chem. Res. Toxicol. 1999; PubMed Scopus Google Scholar, Arch. Biochem. Biophys. 1999; PubMed Scopus Google Scholar). to that the an important role in the reaction of peroxynitrite with Mn-SOD. In addition, manganese the of species at the active site, which with the critical tyrosine this we have studied the role of the manganese metal center in the decomposition kinetics of peroxynitrite and in peroxynitrite-dependent nitration of the enzyme and residues. shed light on the nature of peroxynitrite reaction with Mn-SOD and further to the that peroxynitrite promote in reacts with human recombinant and in a reaction with second order rate of 1.0 ± 0.2 × 105 and 1.4 ± 0.2 × 105m−1s−1 at pH 7.47 and 37 °C, respectively. The rate constant the reaction with the coli apoenzyme was at order of whereas that of the apo/Mn was comparable with that of the that the reaction between Mn-SOD and peroxynitrite on the presence of the metal in the active site. The of peroxynitrite with are therefore, are to in In this the of peroxynitrite with Mn-SOD is to that mitochondrial L. M. R. J. Biol. Chem. Full Text PDF PubMed Google Scholar), L. M. R. R. Arch. Biochem. Biophys. 1995; PubMed Scopus Google Scholar), McCord 1995; PubMed Scopus Google Scholar), and R. G. P. R. Eur. J. Biochem. 1993; PubMed Scopus Google rate constant the reaction between peroxynitrite and the zinc-substituted apoenzyme that the decomposition kinetics of peroxynitrite also affected by the metal zinc J.D. Annu. Rev. Biochem. 1999; PubMed Scopus Google Scholar). rate the reaction of peroxynitrite with Mn(tbap) and Zn(tbap), that the zinc-substituted porphyrin reacts with peroxynitrite manganese The decomposition of peroxynitrite in the presence of Mn-SOD and Mn(tbap) is to a reaction which the of the metal ion G. I. I. Fridovich I. R. Chem. Res. Toxicol. 1999; PubMed Scopus Google Scholar, J. Chem. 1995; Scopus Google Scholar). However, in the presence of the zinc-substituted apoenzyme or Zn(tbap), peroxynitrite decomposition a different that the of the zinc ion a reaction with Mn-SOD to the of of low molecular weight in a In addition, and the human recombinant Mn-SOD PubMed Scopus Google Scholar, H. T. K. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar), peroxynitrite promoted the of the coli enzyme by the nitration of tyrosine in the apoenzyme radical and tyrosine nitration, the manganese ion an important role in tyrosine nitration in the The species a ion to the metal H. L. M. C. J. J. M. Arch. Biochem. Biophys. PubMed Scopus Google Scholar, H. L. J. M. Arch. Biochem. Biophys. PubMed Scopus Google Scholar) or an G. I. I. Fridovich I. R. Chem. Res. Toxicol. 1999; PubMed Scopus Google Scholar, J. Chem. 1995; Scopus Google Scholar). the of peroxynitrite decomposition in the presence of Mn-SOD kinetics that the enzyme is in the reaction with peroxynitrite, nitration is a In metal to or are to promote nitration of this is with on synthase and H. L. J. M. Arch. Biochem. Biophys. PubMed Scopus Google Scholar, 1996; PubMed Scopus Google Scholar, M. C. Biol. Chem. 1997; PubMed Scopus Google coli Mn-SOD tyrosine have different of by the of the the is to the and and and but tyrosine is the to the active site, only at from the manganese The of peroxynitrite to the active site, by the in the and reaction with the manganese ion to the of species a to the that tyrosine is the tyrosine most to nitration by peroxynitrite PubMed Scopus Google Scholar, H. T. K. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google the of Mn-SOD ± (1Weisiger R.A. Fridovich I. J. Biol. Chem. 1973; 248: 3582-3592Abstract Full Text PDF PubMed Google Scholar, Y. Higashiyama S. Kijma Y. Suzuki Y. Kawano K. Akiyama M. Kawata S. Tarui S. Deutsch H.F. Taniguchi N. Eur. J. Biochem. 1990; 194: 713-720Crossref PubMed Scopus (57) Google Scholar, S. J. Biochem. PubMed Scopus Google Scholar, J.D. McCord Fridovich I. Methods Enzymol. PubMed Scopus Google and that in ± in and and R. the enzyme molecular kDa) and mitochondrial a of Mn-SOD the of ± was In to in the Mn-SOD from nitration and in the and presence of the role of a mitochondrial antioxidant and the on the of nitration and of the enzyme in In this Mn-SOD to with P. H. Eur. J. Biochem. PubMed Scopus Google Scholar) associated to the of mitochondrial superoxide production, of peroxynitrite a the Mn-SOD is a critical mitochondrial nitration a that promote and cell to nitration of Mn-SOD tyrosine in a mitochondrial and cellular under conditions of peroxynitrite Manganese-superoxide dismutase (Mn-SOD) is the SOD isoform1found in the mitochondrial matrix of eukaryotes and in a variety of prokaryotes (1Weisiger R.A. Fridovich I. J. Biol. Chem. 1973; 248: 3582-3592Abstract Full Text PDF PubMed Google Scholar, 2Keele Jr., B.B. McCord J. Fridovich I. J. Biol. Chem. 1970; 245: 6176-6181Abstract Full Text PDF PubMed Google Scholar, 3Beyer W. Imlay J. Fridovich I. Prog. Nucleic Acids Res. Mol. Biol. 1991; 40: 221-253Crossref PubMed Scopus (341) Google Scholar). Mn-SODs from different organisms are homologous and have a manganese ion in the active site. Whereas the human mitochondrial enzyme is a homotetramer (∼88 kDa) (4Matsuda Y. Higashiyama S. Kijma Y. Suzuki Y. Kawano K. Akiyama M. Kawata S. Tarui S. Deutsch H.F. Taniguchi N. Eur. J. Biochem. 1990; 194: 713-720Crossref PubMed Scopus (57) Google Scholar), Escherichia coli Mn-SOD (45.8 kDa) is a dimer (3Beyer W. Imlay J. Fridovich I. Prog. Nucleic Acids Res. Mol. Biol. 1991; 40: 221-253Crossref PubMed Scopus (341) Google Scholar). Mitochondria are essential organelles where most of the cell superoxide (O⨪2) is produced (5Turrens J.F. Freeman B.A. Levitt J.G. Crapo J.D. Arch. Biochem. Biophys. 1982; 217: 401-410Crossref PubMed Scopus (353) Google Scholar, 6Boveris A. Methods Enzymol. 1984; 105: 429-435Crossref PubMed Scopus (417) Google Scholar), and therefore, Mn-SOD plays an active role detoxifying the cell from this species. In addition, pharmacological agents and cytokines that promote intracellular reactive oxygen species production, like paraquat (7Krall J. Bagley A.C. Mullenbach G.T. Hallewell R.A. Lynch R.E. J. Biol. Chem. 1988; 263: 1910-1914Abstract Full Text PDF PubMed Google Scholar) and tumor necrosis factor-α (8Liu R. Buettner G.R. Oberley L. Free Radic. Biol. Med. 2000; 28: 1197-1205Crossref PubMed Scopus (41) Google Scholar), induce Mn-SOD expression. Experiments with knock-out mice shed further light on the relevance of this enzyme, with Mn-SOD-deficient mice surviving only up to 3 weeks of age (9Lebovitz R.M. Zhang H. Vogel H. Cartwright Jr., J. Dionne L. Lu N. Huang S. Matzuk M.M. Proc. Natl. Acad. Sci. U. S. A. 1996; 93: 9782-9787Crossref PubMed Scopus (824) Google Scholar, 10Li Y. Huang T.-T. Carlson E.J. Melov S. Ursell P.C. Olson J.L. Noble L.J. Yoshimura M.P. Berger C. Chan P.H. Wallace D.C. Epstein C.J. Nat. Genet. 1995; 11: 376-381Crossref PubMed Scopus (1437) Google Scholar) and presenting many features of mitochondrial disease associated with reactive oxygen species toxicity (11Melov S. Coskun P. Patel M. Tuinstra R. Cottrell B. Jun A.S. Zastawny T.H. Dizdaroglu M. Goodman S.I. Huang T. Miziorko H. Epstein C.J. Wallace D.C. Proc. Natl. Acad. Sci. U. S. A. 1999; 96: 846-851Crossref PubMed Scopus (488) Google Scholar). oxide (NO⋅) is a relatively unreactive free radical formed by nitric oxide synthase (12Gross S.S. Wolin M.S. Annu. Rev. Physiol. 1995; 57: 737-769Crossref PubMed Scopus (820) Google Scholar). However, fast reaction of nitric oxide with superoxide gives rise to peroxynitrite anion (ONOO−), a potent oxidant (13Huie R.E. Padmaja S. Free Radic. Res. Commun. 1993; 18: 195-199Crossref PubMed Scopus (2006) Google Scholar, 14Goldstein S. Czapski G. Free Radic. Biol. Med. 1995; 19: 505-510Crossref PubMed Scopus (376) Google Scholar, 15Kissner R. Nauser T. Bugnonm P. Lyem P.G. Koppenol W.H. Chem. Res. Toxicol. 1997; 10: 1285-1292Crossref PubMed Scopus (560) Google Scholar). Peroxynitrite is formed during sepsis, inflammation, excitotoxicity, and ischemia-reperfusion of tissues, conditions under which the cellular production of nitric oxide and superoxide increase (12Gross S.S. Wolin M.S. Annu. Rev. Physiol. 1995; 57: 737-769Crossref PubMed Scopus (820) Google Scholar, 16Omar B. McCord J. Downey J. Sies H. Oxidative Stress: Oxidants and Antioxidants. Academic Press Inc, San Diego1991: 493-527Google Scholar, A. M. G. Sies H. Oxidative Oxidants and Antioxidants. Academic Press Inc, San Diego1991: Scholar, Huang M. J. 1999; 19: PubMed Google Scholar), and in with the of the presence of nitric oxide synthase in the P. C. 1997; PubMed Scopus Google Scholar, C. A. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar, A. C. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar), with the of nitric oxide J. and Scholar), the of peroxynitrite and the relevance of with Mn-SOD peroxynitrite in but inactivated by peroxynitrite. nitration of tyrosine of human Mn-SOD results in enzyme in vitro PubMed Scopus Google Scholar, H. T. K. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar). The presence of a nitrated and enzyme in human Proc. Natl. Acad. Sci. U. S. A. 1996; Scopus Google Scholar) the relevance of this in Mn-SOD to tyrosine nitration, to an increase in peroxynitrite that in mitochondrial R. M. L. R. Arch. Biochem. Biophys. PubMed Scopus Google Scholar) and cell P. U. C. J. Biol. Chem. 1999; Full Text Full Text PDF Scopus Google Scholar). Peroxynitrite decomposition is by a variety of R. A. B. G. H. L.J. Academic San Google Scholar). are like H. L. M. C. J. J. M. Arch. Biochem. Biophys. PubMed Scopus Google M.S. Padmaja S. Koppenol W.H. Chem. Res. Toxicol. 1996; PubMed Scopus Google Scholar), A. Freeman B. M. R. Arch. Biochem. Biophys. 1996; PubMed Scopus Google Scholar), and transition H. L. M. C. J. J. M. Arch. Biochem. Biophys. PubMed Scopus Google Scholar) that the of the and to the of species. In the of acid to radical and with yields up to R. A. B. G. H. L.J. Academic San Google Scholar, J. Freeman B.A. Proc. Natl. Acad. Sci. U. S. A. 1990; PubMed Scopus Google Scholar), in nitration yields in the of H. L. M. C. J. J. M. Arch. Biochem. Biophys. PubMed Scopus Google Scholar, M.S. Padmaja S. Koppenol W.H. Chem. Res. Toxicol. 1996; PubMed Scopus Google Scholar). In the of transition and SOD nitration yields are obtained H. L. M. C. J. J. M. Arch. Biochem. Biophys. PubMed Scopus Google Scholar, G. L. R. Chem. Res. Toxicol. 1997; 10: PubMed Scopus Google Scholar, G. I. I. Fridovich I. R. Chem. Res. Toxicol. 1999; PubMed Scopus Google Scholar, Arch. Biochem. Biophys. 1999; PubMed Scopus Google Scholar). to that the an important role in the reaction of peroxynitrite with Mn-SOD. In addition, manganese the of species at the active site, which with the critical tyrosine In this we have studied the role of the manganese metal center in the decomposition kinetics of peroxynitrite and in peroxynitrite-dependent nitration of the enzyme and residues. shed light on the nature of peroxynitrite reaction with Mn-SOD and further to the that peroxynitrite promote in reacts with human recombinant and in a reaction with second order rate of 1.0 ± 0.2 × 105 and 1.4 ± 0.2 × 105m−1s−1 at pH 7.47 and 37 °C, respectively. The rate constant the reaction with the coli apoenzyme was at order of whereas that of the apo/Mn was comparable with that of the that the reaction between Mn-SOD and peroxynitrite on the presence of the metal in the active site. The of peroxynitrite with are therefore, are to in In this the of peroxynitrite with Mn-SOD is to that mitochondrial L. M. R. J. Biol. Chem. Full Text PDF PubMed Google Scholar), L. M. R. R. Arch. Biochem. Biophys. 1995; PubMed Scopus Google Scholar), McCord 1995; PubMed Scopus Google Scholar), and R. G. P. R. Eur. J. Biochem. 1993; PubMed Scopus Google rate constant the reaction between peroxynitrite and the zinc-substituted apoenzyme that the decomposition kinetics of peroxynitrite also affected by the metal zinc J.D. Annu. Rev. Biochem. 1999; PubMed Scopus Google Scholar). rate the reaction of peroxynitrite with Mn(tbap) and Zn(tbap), that the zinc-substituted porphyrin reacts with peroxynitrite manganese The decomposition of peroxynitrite in the presence of Mn-SOD and Mn(tbap) is to a reaction which the of the metal ion G. I. I. Fridovich I. R. Chem. Res. Toxicol. 1999; PubMed Scopus Google Scholar, J. Chem. 1995; Scopus Google Scholar). However, in the presence of the zinc-substituted apoenzyme or Zn(tbap), peroxynitrite decomposition a different that the of the zinc ion a reaction with Mn-SOD to the of of low molecular weight in a In addition, and the human recombinant Mn-SOD PubMed Scopus Google Scholar, H. T. K. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar), peroxynitrite promoted the of the coli enzyme by the nitration of tyrosine in the apoenzyme radical and tyrosine nitration, the manganese ion an important role in tyrosine nitration in the The species a ion to the metal H. L. M. C. J. J. M. Arch. Biochem. Biophys. PubMed Scopus Google Scholar, H. L. J. M. Arch. Biochem. Biophys. PubMed Scopus Google Scholar) or an G. I. I. Fridovich I. R. Chem. Res. Toxicol. 1999; PubMed Scopus Google Scholar, J. Chem. 1995; Scopus Google Scholar). the of peroxynitrite decomposition in the presence of Mn-SOD kinetics that the enzyme is in the reaction with peroxynitrite, nitration is a In metal to or are to promote nitration of this is with on synthase and H. L. J. M. Arch. Biochem. Biophys. PubMed Scopus Google Scholar, 1996; PubMed Scopus Google Scholar, M. C. Biol. Chem. 1997; PubMed Scopus Google coli Mn-SOD tyrosine have different of by the of the the is to the and and and but tyrosine is the to the active site, only at from the manganese The of peroxynitrite to the active site, by the in the and reaction with the manganese ion to the of species a to the that tyrosine is the tyrosine most to nitration by peroxynitrite PubMed Scopus Google Scholar, H. T. K. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google the of Mn-SOD ± (1Weisiger R.A. Fridovich I. J. Biol. Chem. 1973; 248: 3582-3592Abstract Full Text PDF PubMed Google Scholar, Y. Higashiyama S. Kijma Y. Suzuki Y. Kawano K. Akiyama M. Kawata S. Tarui S. Deutsch H.F. Taniguchi N. Eur. J. Biochem. 1990; 194: 713-720Crossref PubMed Scopus (57) Google Scholar, S. J. Biochem. PubMed Scopus Google Scholar, J.D. McCord Fridovich I. Methods Enzymol. PubMed Scopus Google and that in ± in and and R. the enzyme molecular kDa) and mitochondrial a of Mn-SOD the of ± was In to in the Mn-SOD from nitration and in the and presence of the role of a mitochondrial antioxidant and the on the of nitration and of the enzyme in In this Mn-SOD to with P. H. Eur. J. Biochem. PubMed Scopus Google Scholar) associated to the of mitochondrial superoxide production, of peroxynitrite a the Mn-SOD is a critical mitochondrial nitration a that promote and cell to nitration of Mn-SOD tyrosine in a mitochondrial and cellular under conditions of peroxynitrite Peroxynitrite reacts with human recombinant and in a reaction with second order rate of 1.0 ± 0.2 × 105 and 1.4 ± 0.2 × 105m−1s−1 at pH 7.47 and 37 °C, respectively. The rate constant the reaction with the coli apoenzyme was at order of whereas that of the apo/Mn was comparable with that of the that the reaction between Mn-SOD and peroxynitrite on the presence of the metal in the active site. The of peroxynitrite with are therefore, are to in In this the of peroxynitrite with Mn-SOD is to that mitochondrial L. M. R. J. Biol. Chem. Full Text PDF PubMed Google Scholar), L. M. R. R. Arch. Biochem. Biophys. 1995; PubMed Scopus Google Scholar), McCord 1995; PubMed Scopus Google Scholar), and R. G. P. R. Eur. J. Biochem. 1993; PubMed Scopus Google Scholar). The rate constant the reaction between peroxynitrite and the zinc-substituted apoenzyme that the decomposition kinetics of peroxynitrite also affected by the metal zinc J.D. Annu. Rev. Biochem. 1999; PubMed Scopus Google Scholar). rate the reaction of peroxynitrite with Mn(tbap) and Zn(tbap), that the zinc-substituted porphyrin reacts with peroxynitrite manganese The decomposition of peroxynitrite in the presence of Mn-SOD and Mn(tbap) is to a reaction which the of the metal ion G. I. I. Fridovich I. R. Chem. Res. Toxicol. 1999; PubMed Scopus Google Scholar, J. Chem. 1995; Scopus Google Scholar). However, in the presence of the zinc-substituted apoenzyme or Zn(tbap), peroxynitrite decomposition a different that the of the zinc ion a Peroxynitrite reaction with Mn-SOD to the of of low molecular weight in a In addition, and the human recombinant Mn-SOD PubMed Scopus Google Scholar, H. T. K. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar), peroxynitrite promoted the of the coli enzyme by the nitration of tyrosine in the apoenzyme radical and tyrosine nitration, the manganese ion an important role in tyrosine nitration in the The species a ion to the metal H. L. M. C. J. J. M. Arch. Biochem. Biophys. PubMed Scopus Google Scholar, H. L. J. M. Arch. Biochem. Biophys. PubMed Scopus Google Scholar) or an G. I. I. Fridovich I. R. Chem. Res. Toxicol. 1999; PubMed Scopus Google Scholar, J. Chem. 1995; Scopus Google Scholar). the of peroxynitrite decomposition in the presence of Mn-SOD kinetics that the enzyme is in the reaction with peroxynitrite, nitration is a In metal to or are to promote nitration of this is with on synthase and H. L. J. M. Arch. Biochem. Biophys. PubMed Scopus Google Scholar, 1996; PubMed Scopus Google Scholar, M. C. Biol. Chem. 1997; PubMed Scopus Google Scholar). coli Mn-SOD tyrosine have different of by the of the the is to the and and and but tyrosine is the to the active site, only at from the manganese The of peroxynitrite to the active site, by the in the and reaction with the manganese ion to the of species a to the that tyrosine is the tyrosine most to nitration by peroxynitrite PubMed Scopus Google Scholar, H. T. K. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar). the of Mn-SOD ± (1Weisiger R.A. Fridovich I. J. Biol. Chem. 1973; 248: 3582-3592Abstract Full Text PDF PubMed Google Scholar, Y. Higashiyama S. Kijma Y. Suzuki Y. Kawano K. Akiyama M. Kawata S. Tarui S. Deutsch H.F. Taniguchi N. Eur. J. Biochem. 1990; 194: 713-720Crossref PubMed Scopus (57) Google Scholar, S. J. Biochem. PubMed Scopus Google Scholar, J.D. McCord Fridovich I. Methods Enzymol. PubMed Scopus Google and that in ± in and and R. the enzyme molecular kDa) and mitochondrial a of Mn-SOD the of ± was In to in the Mn-SOD from nitration and in the and presence of the role of a mitochondrial antioxidant and the on the of nitration and of the enzyme in In this Mn-SOD to with P. H. Eur. J. Biochem. PubMed Scopus Google Scholar) associated to the of mitochondrial superoxide production, of peroxynitrite a the Since Mn-SOD is a critical mitochondrial nitration a that promote and cell to nitration of Mn-SOD tyrosine in a mitochondrial and cellular under conditions of peroxynitrite and in the and respectively.