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Xanthine Oxidase Reaction with Nitric Oxide and Peroxynitrite

https://doi.org/10.1006/abbi.1998.0675Get rights and content

Abstract

Nitric oxide (·NO) and peroxynitrite (ONOO) inhibit enzymes that depend on metal cofactors or oxidizable amino acids for activity. Since xanthine oxidase (XO) is a 2(2Fe2S) enzyme having essential sulfhydryl groups linked with Mo–pterin cofactor function, the influence of ·NO and ONOOon purified bovine XO was determined. Physiological (≤1 μM) and supraphysiological (≤100 μM) concentrations of dissolved ·NO gas did not inhibit the catalytic activity or alter the spectral characteristics of XO at 25°C and pH 7.0, differing from reports showing XO inhibition by ·NO. The apparent decrease in XO activity observed previously was the result of depressed rates of uric acid accumulation in XO assay systems, due to ONOO-mediated oxidation of uric acid upon reaction of residual ·NO with XO-derived superoxide (O•−2). Nitric oxide derived fromS-nitrosoglutathione also did not inhibit cultured vascular endothelial cell XO activity. In contrast, purified and vascular endothelial cell catalase, a heme enzyme reversibly inhibited by ·NO, was inhibited by similar concentrations and rates of production of ·NO. In contrast to ·NO, ONOOinhibited XO (0.2 μM, 50 mU/ml) with an IC50of 57 μM (for 3 μM/min infusion of ONOO) or 120 μM (for bolus addition of ONOO). Addition of 1% bovine serum albumin, 50 μM xanthine, or 10 μM uric acid protected XO from inactivation by ONOO. Thus, in the presence of purine substrates and other more readily oxidized components of the biological milieu, XO should not be inhibited by either ·NO or ONOO. These observations reveal that ·NO will not serve as an indirect antioxidant by inhibiting XO-derived production of reactive species and that the XO-derived products O•−2and uric acid readily modify the reactivities of ·NO and ONOO.

References (56)

  • M.W. Radomski et al.

    Biochem. Biophys. Res. Commun.

    (1987)
  • B.A. Freeman et al.

    Adv. Pharmacol.

    (1995)
  • H. Rubbo et al.

    J. Biol. Chem.

    (1994)
  • A. Cassina et al.

    Arch. Biochem. Biophys.

    (1996)
  • M. Lepoivre et al.

    J. Biol. Chem.

    (1994)
  • J.S. Beckman et al.

    Methods Enzymol.

    (1994)
  • R. Radi et al.

    J. Biol. Chem.

    (1991)
  • R. Radi et al.

    Arch. Biochem. Biophys.

    (1991)
  • P. Wang et al.

    J. Biol. Chem.

    (1996)
  • M.G. Salgo et al.

    Arch. Biochem. Biophys.

    (1995)
  • L. Castro et al.

    J. Biol. Chem.

    (1994)
  • A. Hausladen et al.

    J. Biol. Chem.

    (1994)
  • S. Sakuma et al.

    Biochem. Biophys. Res. Commun.

    (1997)
  • W.D. Johnson et al.

    Am. Heart J.

    (1991)
  • C.M. Grum et al.

    J. Crit. Care

    (1987)
  • J.S. Beckman et al.

    Methods

    (1995)
  • J.S. Beckman et al.

    Free Radical Biol. Med.

    (1989)
  • M. Kanda et al.

    J. Biol. Chem.

    (1972)
  • A. Paler-Martinez et al.

    Arch. Biochem. Biophys.

    (1994)
  • L. Zhu et al.

    Arch. Biochem. Biophys.

    (1992)
  • H. Ischiropoulos et al.

    Arch. Biochem. Biophys.

    (1992)
  • Y.M. Kim et al.

    J. Biol. Chem.

    (1995)
  • L. Castro et al.

    Arch. Biochem. Biophys.

    (1996)
  • P.L. Bounds et al.

    Free Radical Biol. Med.

    (1991)
  • H. Rubbo et al.

    Chem. Res. Toxicol.

    (1996)
  • W.B. Poss et al.

    J. Appl. Physiol.

    (1995)
  • S. Adnot et al.

    Monaldi Arch. Chest Dis.

    (1996)
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      However, we also observed that under excess of •NO, the extent of conversion of xanthine into uric acid was also decreased with increasing •NO flux (Fig. 7C). This may be due to •NO-dependent inhibition of the enzyme (40–42). Assuming that the rate of O2̇̄ generation is proportional to XO activity, and therefore, to the rate (and the yield) of uric acid formation, we normalized the amount of COH (“corrected”) to the yield of uric acid (and thus to O2̇̄).

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    Lancaster, J. R.

    1

    To whom correspondence should be addressed at Department of Anesthesiology, 946 Tinsley Harrison Tower, 619 South 19th Street, University of Alabama at Birmingham, Birmingham, AL 35233-6810. Fax: (205) 934-7437. E-mail:[email protected].

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