1. N-hydroxylamine is not an intermediate in the conversion of L-arginine to an activator of soluble guanylate cyclase in neuroblastoma N1E-115 cells
- Author
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Gerald M. Rosen, Sovitj Pou, Esam E. El-Fakahany, and Wanida S. Pou
- Subjects
GUCY1B3 ,Guanylate kinase ,Hydroxylamine ,Arginine ,Hydroxylamines ,Biochemistry ,Nitric oxide ,Cell Line ,Superoxide dismutase ,chemistry.chemical_compound ,Mice ,Neuroblastoma ,Cytosol ,Animals ,Molecular Biology ,Cyclic GMP ,GUCY1A2 ,biology ,Activator (genetics) ,GUCY1A3 ,Cell Biology ,Guanylate cyclase 2C ,Kinetics ,chemistry ,Guanylate Cyclase ,biology.protein ,Calcium ,Research Article - Abstract
This study evaluates the role of N-hydroxylamine (NH2OH) in activating soluble guanylate cyclase in the mouse neuroblastoma clone N1E-115. It has been proposed that NH2OH is a putative intermediate in the biochemical pathway for the generation of nitric oxide (NO)/endothelium-derived relaxing factor (EDRF) from L-arginine. NH2OH caused a time- and concentration-dependent increase in cyclic GMP formation in intact cells. This response was not dependent on Ca2+. In cytosol preparations the activation of guanylate cyclase by L-arginine was dose-dependent and required Ca2+ and NADPH. In contrast, NH2OH itself did not activate cytosolic guanylate cyclase but it inhibited the basal activity of this enzyme in a concentration-dependent manner. The formation of cyclic GMP in the cytosolic fractions in response to NH2OH required the addition of catalase and H2O2. On the other hand, catalase and/or H2O2 lead to a decrease in L-arginine-induced cyclic GMP formation. Furthermore, NH2OH inhibited L-arginine- and sodium nitroprusside-induced cyclic GMP formation in the cytosol. The inhibition of L-arginine-induced cyclic GMP formation in the cytosol by NH2OH was not reversed by the addition of superoxide dismutase. These data strongly suggest that NH2OH is not a putative intermediate in the metabolism of L-arginine to an activator of guanylate cyclase.
- Published
- 1991