RT Journal Article SR Electronic T1 An Inhibitor of Protein Arginine Methyltransferases, 7,7′-Carbonylbis(azanediyl)bis(4-hydroxynaphthalene-2-sulfonic acid (AMI-1), Is a Potent Scavenger of NADPH-Oxidase–Derived Superoxide JF Molecular Pharmacology JO Mol Pharmacol FD American Society for Pharmacology and Experimental Therapeutics SP 280 OP 287 DO 10.1124/mol.109.061077 VO 77 IS 2 A1 Chen, Feng A1 Fulton, David J. R. YR 2010 UL http://molpharm.aspetjournals.org/content/77/2/280.abstract AB The methylation of proteins is an important post-translational mechanism that has been established to influence the activity of nuclear and nucleic acid binding proteins. Much less is known about the importance of protein methylation in the regulation of cytosolic proteins. Increased methylation of proteins is observed in cardiovascular disease and occurs in conjunction with elevated production of reactive oxygen species. However, the nature of the relationship between reactive oxygen species and protein methylation is poorly understood. Therefore, the goal of the current study was to determine whether protein methylation influences the catalytic activity of the NADPH oxidases (Nox), which are a family of enzymes responsible for the generation of superoxide. We found that the selective inhibitor of protein arginine methyltransferases 7,7′-carbonylbis(azanediyl)bis(4-hydroxynaphthalene-2-sulfonic acid (AMI-1) was a potent antagonist of Nox-derived superoxide production. However, structurally and mechanistically dissimilar inhibitors of protein methylation and coexpression of protein arginine methyltransferase 1 did not influence Nox activity. Rather, the effect of AMI-1 was rapidly reversible and could be demonstrated in an assay using chemically synthesized superoxide. We conclude that protein methylation does not regulate the activity of NADPH-oxidases and that AMI-1 is a potent antioxidant with a greater potency than 4,5-dihydroxy-1,3-benzenedisulfonic acid (Tiron) and 4-hydroxy-2,2,6,6-tetramethylpiperydine-1-oxyl (Tempol).