Kinetics of the oxidation of reduced Cu,Zn-superoxide dismutase by peroxymonocarbonate

Kalina Ranguelova; Douglas Ganini; Marcelo G. Bonini; Robert E. London; Ronald P. Mason

doi:10.1016/j.freeradbiomed.2012.04.029

Kinetics of the oxidation of reduced Cu,Zn-superoxide dismutase by peroxymonocarbonate

Kalina Ranguelova, Douglas Ganini, Marcelo G. Bonini, Robert E. London, Ronald P. Mason^*

^*Corresponding author for this work

Medicine, Hematology Oncology Division

Research output: Contribution to journal › Article › peer-review

19 Scopus citations

Abstract

Kinetic evidence is reported for the role of the peroxymonocarbonate, HOOCO₂^-, as an oxidant for reduced Cu,Zn-superoxide dismutase-Cu(I) (SOD1) during the peroxidase activity of the enzyme. The formation of this reactive oxygen species results from the equilibrium between hydrogen peroxide and bicarbonate. Recently, peroxymonocarbonate has been proposed to be a key substrate for reduced SOD1 and has been shown to oxidize SOD1-Cu(I) to SOD1-Cu(II) much faster than H₂O₂. We have reinvestigated the kinetics of the reaction between SOD1-Cu(I) and HOOCO ₂^- by using conventional stopped-flow spectrophotometry and obtained a second-order rate constant of k=1600±100 M^-1 s^-1 for SOD1-Cu(I) oxidation by HOOCO₂^-. Our results demonstrate that peroxymonocarbonate oxidizes SOD1-Cu(I) to SOD1-Cu(II) and is in turn reduced to the carbonate anion radical. It is proposed that the dissociation of His61 from the active site Cu(I) in SOD-Cu(I) contributes to this chemistry by facilitating the binding of larger anions, such as peroxymonocarbonate.

Original language	English (US)
Pages (from-to)	589-594
Number of pages	6
Journal	Free Radical Biology and Medicine
Volume	53
Issue number	3
DOIs	https://doi.org/10.1016/j.freeradbiomed.2012.04.029
State	Published - Aug 1 2012

Funding

We acknowledge Mrs. Mary J. Mason and Dr. Ann Motten for their help in the preparation of the manuscript. The authors also thank Dr. Richard S. Magliozzo from Brooklyn College for the use of his stopped-flow spectrophotometer. This work has been supported by the Intramural Research Program of the NIH, NIEHS .

Keywords

Carbonate anion radical
Peroxymonocarbonate
Superoxide dismutase

ASJC Scopus subject areas

Physiology (medical)
Biochemistry

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10.1016/j.freeradbiomed.2012.04.029

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title = "Kinetics of the oxidation of reduced Cu,Zn-superoxide dismutase by peroxymonocarbonate",

abstract = "Kinetic evidence is reported for the role of the peroxymonocarbonate, HOOCO2-, as an oxidant for reduced Cu,Zn-superoxide dismutase-Cu(I) (SOD1) during the peroxidase activity of the enzyme. The formation of this reactive oxygen species results from the equilibrium between hydrogen peroxide and bicarbonate. Recently, peroxymonocarbonate has been proposed to be a key substrate for reduced SOD1 and has been shown to oxidize SOD1-Cu(I) to SOD1-Cu(II) much faster than H2O2. We have reinvestigated the kinetics of the reaction between SOD1-Cu(I) and HOOCO 2- by using conventional stopped-flow spectrophotometry and obtained a second-order rate constant of k=1600±100 M-1 s-1 for SOD1-Cu(I) oxidation by HOOCO2-. Our results demonstrate that peroxymonocarbonate oxidizes SOD1-Cu(I) to SOD1-Cu(II) and is in turn reduced to the carbonate anion radical. It is proposed that the dissociation of His61 from the active site Cu(I) in SOD-Cu(I) contributes to this chemistry by facilitating the binding of larger anions, such as peroxymonocarbonate.",

keywords = "Carbonate anion radical, Peroxymonocarbonate, Superoxide dismutase",

author = "Kalina Ranguelova and Douglas Ganini and Bonini, {Marcelo G.} and London, {Robert E.} and Mason, {Ronald P.}",

note = "Funding Information: We acknowledge Mrs. Mary J. Mason and Dr. Ann Motten for their help in the preparation of the manuscript. The authors also thank Dr. Richard S. Magliozzo from Brooklyn College for the use of his stopped-flow spectrophotometer. This work has been supported by the Intramural Research Program of the NIH, NIEHS .",

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T1 - Kinetics of the oxidation of reduced Cu,Zn-superoxide dismutase by peroxymonocarbonate

AU - Ranguelova, Kalina

AU - Ganini, Douglas

AU - Bonini, Marcelo G.

AU - London, Robert E.

AU - Mason, Ronald P.

N1 - Funding Information: We acknowledge Mrs. Mary J. Mason and Dr. Ann Motten for their help in the preparation of the manuscript. The authors also thank Dr. Richard S. Magliozzo from Brooklyn College for the use of his stopped-flow spectrophotometer. This work has been supported by the Intramural Research Program of the NIH, NIEHS .

PY - 2012/8/1

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N2 - Kinetic evidence is reported for the role of the peroxymonocarbonate, HOOCO2-, as an oxidant for reduced Cu,Zn-superoxide dismutase-Cu(I) (SOD1) during the peroxidase activity of the enzyme. The formation of this reactive oxygen species results from the equilibrium between hydrogen peroxide and bicarbonate. Recently, peroxymonocarbonate has been proposed to be a key substrate for reduced SOD1 and has been shown to oxidize SOD1-Cu(I) to SOD1-Cu(II) much faster than H2O2. We have reinvestigated the kinetics of the reaction between SOD1-Cu(I) and HOOCO 2- by using conventional stopped-flow spectrophotometry and obtained a second-order rate constant of k=1600±100 M-1 s-1 for SOD1-Cu(I) oxidation by HOOCO2-. Our results demonstrate that peroxymonocarbonate oxidizes SOD1-Cu(I) to SOD1-Cu(II) and is in turn reduced to the carbonate anion radical. It is proposed that the dissociation of His61 from the active site Cu(I) in SOD-Cu(I) contributes to this chemistry by facilitating the binding of larger anions, such as peroxymonocarbonate.

AB - Kinetic evidence is reported for the role of the peroxymonocarbonate, HOOCO2-, as an oxidant for reduced Cu,Zn-superoxide dismutase-Cu(I) (SOD1) during the peroxidase activity of the enzyme. The formation of this reactive oxygen species results from the equilibrium between hydrogen peroxide and bicarbonate. Recently, peroxymonocarbonate has been proposed to be a key substrate for reduced SOD1 and has been shown to oxidize SOD1-Cu(I) to SOD1-Cu(II) much faster than H2O2. We have reinvestigated the kinetics of the reaction between SOD1-Cu(I) and HOOCO 2- by using conventional stopped-flow spectrophotometry and obtained a second-order rate constant of k=1600±100 M-1 s-1 for SOD1-Cu(I) oxidation by HOOCO2-. Our results demonstrate that peroxymonocarbonate oxidizes SOD1-Cu(I) to SOD1-Cu(II) and is in turn reduced to the carbonate anion radical. It is proposed that the dissociation of His61 from the active site Cu(I) in SOD-Cu(I) contributes to this chemistry by facilitating the binding of larger anions, such as peroxymonocarbonate.

KW - Carbonate anion radical

KW - Peroxymonocarbonate

KW - Superoxide dismutase

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Kinetics of the oxidation of reduced Cu,Zn-superoxide dismutase by peroxymonocarbonate

Abstract

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Keywords

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