The Daily Bulletin Archive

Please join the Chemistry and Physics departments for the seminar "Metal-Mediated NOxchemistry: Relevance to the Global N-cycle," presented by Erwin Abucayon, postdoctoral research fellow in the University of Oklahoma's Richter-Addo research group, on Thursday, March 19, from 12:15 to 1:30 p.m. in Science and Mathematics Complex 176.

Nitrogen oxides (NOx) are employed in biology to serve several functions that are significant to human health. These species are also involved as important intermediates in the global N-cycle. Most of their functions stem from their interactions with metalloproteins. For example, nitric oxide (NO), the simplest form of NOx species, interacts with heme proteins to elicit its function as a vasodilator. Its related sibling molecule HNO is a promising drug candidate for cardiac muscle relaxation and constriction. Importantly, heme-HNO species are involved as key intermediates in the NO detoxification by fungal cyt P450 NO reductase en route to nitrous oxide (N2O) formation. The conversion of NO-to-N2O is an integral component of denitrification. This transformation is not only important as a significant component of the global N-cycle but is also relevant to climate change, as N2O is a more potent greenhouse gas than the well-known CO2. N2O is generated in biology via the N?N bond coupling of two NO molecules mediated by monoheme and heme/non-heme deFe-active sites of nitric oxide reductases (NORs) in fungal and bacterial denitrification, respectively. 

This talk will highlight some of our findings on the generation of heme model-HNO/RNO compounds and their involvement in N?N bond formation reactions to generate N2O as part of the global N-cycle. We show that with appropriate choice of synthetic models, critical intermediates along both the fungal and bacterial pathways can be obtained and studied, yielding long-sought-after information regarding how metal active sites in the NOR proteins can enable the critical N–N bond formation step to generate N2O. 

My planned research at Buffalo State College will involve metal-based reactivity of SOx/SR2compounds with N2O and related NOxspecies as oxidants.