Chemistry. The oxidation of hydroxylamines with H2O2 mediated by myoglobin.

ÁLVAREZ, L; MARTI, M; SUAREZ, S; DOCTOROVICH, FABIO

Santiago de Querétaro

Congreso; A. V Latin Ameri- can Meeting on Biological Inorganic Chemistry.; 2016

Nitroxyl (HNO) has biological and pharmacological properties compared to those of other nitrogen oxides. It regulates calcium channels in both the cardiovascular and nervous systems. In addition, HNO donors increase cardiac function in an additive and independent manner to β-adrenergic signaling. Such findings have led recently to extensive investigation of the chemical, biochemical and pharmacological properties of HNO.Many heme proteins function as peroxidases in the catalyzed oxidation of a wide range of substrates. Despite the protective and functional utility of peroxidases, an increase in peroxidase activity has been implicated in the pathology of a number of diseases.In this work, we examined the ability of Myoglobin to produce HNO from peroxidation of hydroxylamines such as NH2OH and NHCH3OH with H2O2 using both experimental and computational approach.In previous works1 it has been proposed that this reaction mediated by different hemeproteins ocurrs by the following mechanism: Scheme 1 According to this mechanism we studied the reaction kinetic of these two different steps following spectral changes that occurred during the reaction. In addition, the HNO production was confirmed using an electrochemical method with the Cobalt Porphyrin bound to gold developed in our group.2 In order to have an insight in the reaction mechanism, we performed QM/MM experiments calculating the energy barrier for the HNO production considering different spin states. It can be concluded that the oxidation of hydroxilamines with H2O2 mediated by Myoglobin produced HNO and it could be a possible endogenous source of HNO.