Ricerc@Sapienza

Abstract: Hydrogen sulfide (H2S) is often called the third gasotransmitter (after nitric oxide and carbon monoxide), or endogenous gaseous signaling molecule. This compound plays important roles in organisms from different taxonomic groups, from bacteria to animals and humans. In mammalian cells, H2S has a cytoprotective effect at nanomolar concentrations, but becomes cytotoxic at higher concentrations. The primary target of H2S is mitochondria.

With a view to characterizing the influence of the electronic structure of the Fe atom on the nature of its bond with dioxygen (O-2) in heme compounds, a study of the UV/Vis action spectra and binding energies of heme-O-2 molecules has been undertaken in the gas phase. The binding reaction of protonated ferrous heme [Fe-II-hemeH](+) with O-2 has been studied in the gas phase by determining the equilibrium of complexed [Fe-II-hemeH(O-2)](+) with uncomplexed protonated heme in an ion trap at controlled temperatures.