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Regulation of eNOS-derived superoxide by endogenous methylarginines.
Biochemistry. 2008 Jul 08; 47(27):7256-63.B

Abstract

The endogenous methylarginines, asymmetric dimethylarginine (ADMA) and N (G)-monomethyl- l-arginine (L-NMMA) regulate nitric oxide (NO) production from endothelial NO synthase (eNOS). Under conditions of tetrahydrobiopterin (BH 4) depletion eNOS also generates (*)O 2 (-); however, the effects of methylarginines on eNOS-derived (*)O 2 (-) generation are poorly understood. Therefore, using electron paramagnetic resonance spin trapping techniques we measured the dose-dependent effects of ADMA and L-NMMA on (*)O 2 (-) production from eNOS under conditions of BH 4 depletion. In the absence of BH 4, ADMA dose-dependently increased NOS-derived (*)O 2 (-) generation, with a maximal increase of 151% at 100 microM ADMA. L-NMMA also dose-dependently increased NOS-derived (*)O 2 (-), but to a lesser extent, demonstrating a 102% increase at 100 microM L-NMMA. Moreover, the native substrate l-arginine also increased eNOS-derived (*)O 2 (-), exhibiting a similar degree of enhancement as that observed with ADMA. Measurements of NADPH consumption from eNOS demonstrated that binding of either l-arginine or methylarginines increased the rate of NADPH oxidation. Spectrophotometric studies suggest, just as for l-arginine and L-NMMA, the binding of ADMA shifts the eNOS heme to the high-spin state, indicative of a more positive heme redox potential, enabling enhanced electron transfer from the reductase to the oxygenase site. These results demonstrate that the methylarginines can profoundly shift the balance of NO and (*)O 2 (-) generation from eNOS. These observations have important implications with regard to the therapeutic use of l-arginine and the methylarginine-NOS inhibitors in the treatment of disease.

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Publisher Full Text (DOI)

Authors+Show Affiliations

Druhan LJ
Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, Ohio 43210, USA.
Forbes SP
No affiliation info available
Pope AJ
No affiliation info available
Chen CA
No affiliation info available
Zweier JL
No affiliation info available
Cardounel AJ
No affiliation info available

MeSH

ArginineBiopterinElectron Spin Resonance SpectroscopyHemeHumansNADPNitric Oxide Synthase Type IIISuperoxidesomega-N-Methylarginine

Pub Type(s)

Journal Article
Research Support, N.I.H., Extramural

Language

eng

PubMed ID

18553936

Citation

Druhan, Lawrence J., et al. "Regulation of eNOS-derived Superoxide By Endogenous Methylarginines." Biochemistry, vol. 47, no. 27, 2008, pp. 7256-63.
Druhan LJ, Forbes SP, Pope AJ, et al. Regulation of eNOS-derived superoxide by endogenous methylarginines. Biochemistry. 2008;47(27):7256-63.
Druhan, L. J., Forbes, S. P., Pope, A. J., Chen, C. A., Zweier, J. L., & Cardounel, A. J. (2008). Regulation of eNOS-derived superoxide by endogenous methylarginines. Biochemistry, 47(27), 7256-63. https://doi.org/10.1021/bi702377a
Druhan LJ, et al. Regulation of eNOS-derived Superoxide By Endogenous Methylarginines. Biochemistry. 2008 Jul 8;47(27):7256-63. PubMed PMID: 18553936.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Regulation of eNOS-derived superoxide by endogenous methylarginines. AU - Druhan,Lawrence J, AU - Forbes,Scott P, AU - Pope,Arthur J, AU - Chen,Chun-An, AU - Zweier,Jay L, AU - Cardounel,Arturo J, Y1 - 2008/06/14/ PY - 2008/6/17/pubmed PY - 2008/7/17/medline PY - 2008/6/17/entrez SP - 7256 EP - 63 JF - Biochemistry JO - Biochemistry VL - 47 IS - 27 N2 - The endogenous methylarginines, asymmetric dimethylarginine (ADMA) and N (G)-monomethyl- l-arginine (L-NMMA) regulate nitric oxide (NO) production from endothelial NO synthase (eNOS). Under conditions of tetrahydrobiopterin (BH 4) depletion eNOS also generates (*)O 2 (-); however, the effects of methylarginines on eNOS-derived (*)O 2 (-) generation are poorly understood. Therefore, using electron paramagnetic resonance spin trapping techniques we measured the dose-dependent effects of ADMA and L-NMMA on (*)O 2 (-) production from eNOS under conditions of BH 4 depletion. In the absence of BH 4, ADMA dose-dependently increased NOS-derived (*)O 2 (-) generation, with a maximal increase of 151% at 100 microM ADMA. L-NMMA also dose-dependently increased NOS-derived (*)O 2 (-), but to a lesser extent, demonstrating a 102% increase at 100 microM L-NMMA. Moreover, the native substrate l-arginine also increased eNOS-derived (*)O 2 (-), exhibiting a similar degree of enhancement as that observed with ADMA. Measurements of NADPH consumption from eNOS demonstrated that binding of either l-arginine or methylarginines increased the rate of NADPH oxidation. Spectrophotometric studies suggest, just as for l-arginine and L-NMMA, the binding of ADMA shifts the eNOS heme to the high-spin state, indicative of a more positive heme redox potential, enabling enhanced electron transfer from the reductase to the oxygenase site. These results demonstrate that the methylarginines can profoundly shift the balance of NO and (*)O 2 (-) generation from eNOS. These observations have important implications with regard to the therapeutic use of l-arginine and the methylarginine-NOS inhibitors in the treatment of disease. SN - 1520-4995 UR - https://www.unboundmedicine.com/medline/citation/18553936/Regulation_of_eNOS_derived_superoxide_by_endogenous_methylarginines_ L2 - https://doi.org/10.1021/bi702377a DB - PRIME DP - Unbound Medicine ER -