Metalloporphyrin catalyzed oxidation of N-hydroxyguanidines: a biomimetic model for the H2O2-dependent activity of nitric oxide synthase.

G M Keseru, G T Balogh, T Karancsi

Index: Bioorg. Med. Chem. Lett. 10(15) , 1775-7, (2000)

Full Text: HTML

Abstract

A chemical model for the H2O2 promoted oxidation by nitric oxide synthase (NOS) has been developed. Biomimetic oxidations were carried out using H2O2 and tetrakis(perfluorophenyl)porphyrinato-iron(III) chloride (FeTPPF20) as a catalyst. Similarly to NOS our model system produces Ndelta-cyanoornithine, citrulline and NO from NOHA and did not oxidize arginine itself. Based on these results we propose a peroxide shunt to be involved in the catalytic cycle of NOS. To the best of our knowledge this is the first chemical system that semiquantitatively mimics NOS activity.