BIOMAT Database Logo BIOMAT Database Logo

Alloxan-dialuric acid cycling: a complex redox mechanism. 2009

Janina A Rosso, and Marcos A Astorga, and Daniel O Martire, and Mónica C Gonzalez
Instituto de Investigaciones Fisicoquimicas Teoricas y Aplicadas, Departamento de Quimica, Universidad Nacional de La Plata, La Plata, Argentina. janina@inifta.unlp.edu.ar

Time-resolved kinetic studies involving the reactions of alloxan (A.H(2)O) with the reducing species superoxide and carbon dioxide radical anions and the reaction of dialuric acid (HA(-)) with sulphate radicals showed that the same radical (AH(.)) was formed either by the one-electron reduction of alloxan or by the one-electron oxidation of dialuric acid. A mechanism including several reversible reactions was proposed and validated. A detailed kinetic analysis yields the following bimolecular rate constants: k(A.H(2)O + [image omitted] ) < 10(5) m ( -1 ) s(-1), k(A.H(2)O + O(2) (-))=(3.4+/-0.5)x10(6) m ( -1 ) s(-1), k(HA(-)+[image omitted] )=(8+/-1)x10(7) m ( -1 ) s(-1) and k(AH(.)+AH(.))=(1.7+/-0.8)x10(8) m ( -1 ) s(-1). From these values, the redox potentials E degrees (A.H(2)O,H(+)/AH(.))=(-290+/-20) mV, E degrees (AH(.)/HA(-))=(277+/-20) mV and E degrees (A.H(2)O,H(+)/HA(-))=(-15+/-20) mV, were obtained.

UI MeSH Term Description Entries
D007700 Kinetics The rate dynamics in chemical or physical systems.
D010084 Oxidation-Reduction A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs (Lehninger, Principles of Biochemistry, 1982, p471). Redox,Oxidation Reduction
D010100 Oxygen An element with atomic symbol O, atomic number 8, and atomic weight [15.99903; 15.99977]. It is the most abundant element on earth and essential for respiration. Dioxygen,Oxygen-16,Oxygen 16
D010782 Photolysis Chemical bond cleavage reactions resulting from absorption of radiant energy. Photodegradation
D005609 Free Radicals Highly reactive molecules with an unsatisfied electron valence pair. Free radicals are produced in both normal and pathological processes. Free radicals include reactive oxygen and nitrogen species (RONS). They are proven or suspected agents of tissue damage in a wide variety of circumstances including radiation, damage from environment chemicals, and aging. Natural and pharmacological prevention of free radical damage is being actively investigated. Free Radical
D005978 Glutathione A tripeptide with many roles in cells. It conjugates to drugs to make them more soluble for excretion, is a cofactor for some enzymes, is involved in protein disulfide bond rearrangement and reduces peroxides. Reduced Glutathione,gamma-L-Glu-L-Cys-Gly,gamma-L-Glutamyl-L-Cysteinylglycine,Glutathione, Reduced,gamma L Glu L Cys Gly,gamma L Glutamyl L Cysteinylglycine
D006861 Hydrogen Peroxide A strong oxidizing agent used in aqueous solution as a ripening agent, bleach, and topical anti-infective. It is relatively unstable and solutions deteriorate over time unless stabilized by the addition of acetanilide or similar organic materials. Hydrogen Peroxide (H2O2),Hydroperoxide,Oxydol,Perhydrol,Superoxol,Peroxide, Hydrogen
D000496 Alloxan Acidic compound formed by oxidation of URIC ACID. It is isolated as an efflorescent crystalline hydrate.
D001463 Barbiturates A class of chemicals derived from barbituric acid or thiobarbituric acid. Many of these are GABA MODULATORS used as HYPNOTICS AND SEDATIVES, as ANESTHETICS, or as ANTICONVULSANTS.
D013431 Sulfates Inorganic salts of sulfuric acid. Sulfate,Sulfates, Inorganic,Inorganic Sulfates

Related Publications

Janina A Rosso, and Marcos A Astorga, and Daniel O Martire, and Mónica C Gonzalez
Influence of oxygen concentration on redox cycling of alloxan and dialuric acid.
December 2005, Hormone and metabolic research = Hormon- und Stoffwechselforschung = Hormones et metabolisme,
Janina A Rosso, and Marcos A Astorga, and Daniel O Martire, and Mónica C Gonzalez
The dialuric acid-alloxan equilibrium.
January 1929, The Biochemical journal,
Janina A Rosso, and Marcos A Astorga, and Daniel O Martire, and Mónica C Gonzalez
Simultaneous quantitative determination of alloxan, GSH and GSSG by HPlc. Estimation of the frequency of redox cycling between alloxan and dialuric acid.
February 2001, Hormone and metabolic research = Hormon- und Stoffwechselforschung = Hormones et metabolisme,
Janina A Rosso, and Marcos A Astorga, and Daniel O Martire, and Mónica C Gonzalez
Pulse radiolytic investigations of the redox system alloxan-dialuric acid: evidence for a radical intermediate.
December 1979, Biochemical and biophysical research communications,
Janina A Rosso, and Marcos A Astorga, and Daniel O Martire, and Mónica C Gonzalez
Radiolysis study of the alloxan-dialuric acid couple. II. The autoxidation of dialuric acid.
October 1981, Radiation research,
Janina A Rosso, and Marcos A Astorga, and Daniel O Martire, and Mónica C Gonzalez
Reactions of alloxan and dialuric acid with the sulfhydryl group.
January 1949, The Journal of biological chemistry,
Janina A Rosso, and Marcos A Astorga, and Daniel O Martire, and Mónica C Gonzalez
Alloxan and dialuric acid; their stabilities and ultraviolet absorption spectra.
January 1949, The Journal of biological chemistry,
Janina A Rosso, and Marcos A Astorga, and Daniel O Martire, and Mónica C Gonzalez
Radical chemistry of alloxan-dialuric acid: role of the superoxide radical.
January 1981, Bulletin europeen de physiopathologie respiratoire,
Janina A Rosso, and Marcos A Astorga, and Daniel O Martire, and Mónica C Gonzalez
[Action of the alloxan-dialuric acid system on the activity of urease].
January 1950, Bollettino della Societa italiana di biologia sperimentale,
Janina A Rosso, and Marcos A Astorga, and Daniel O Martire, and Mónica C Gonzalez
Glutathione dependent reduction of alloxan to dialuric acid catalyzed by thioltransferase (glutaredoxin): a possible role for thioltransferase in alloxan toxicity.
January 1997, Free radical biology & medicine,
Copied contents to your clipboard!