The reaction path of product release in NO detoxification at the active site of truncated hemoglobin N in MCSCF approach

The Multi-Configurational Self-Consistent Field approach with the geometry optimization was applied to the calculation of electronic properties of active site of heme core of truncated hemoglobin N, with the inclusion of [ONOO] functional group and two water molecules. The localized molecular orbitals are employed as a starting set. Two subspaces of full interaction have been used by the construction of MCSCF wavefunction. The first one includes 3d-orbitals of iron atom, and the second contains bonding and antibonding molecular orbitals of peroxynitrite with one unshared electronic pair of the O$_2$ fragment. The reaction is characterized by two transition states; the products are nitrate anion NO$_3^-$ and one unbound water molecule. There arise an evidence of NO$_2$ and NO radicals as the reaction products.