The conversion of the hydroxyl to carboxyl groups is often employed to gain new functionalities in the cellulose chain, especially by using the water-soluble stable
nitroxyl radical 2,2,6,6-tetramethylpyperidine-l-oxyl (TEMPO) [5-8], but also involving the nonpersistent
nitroxyl radicals, as we have recently reported [6, 9, 10].
Antioxidant and pro-oxidant actions of flavonoids: effects on DNA damage induced by nitric oxide, peroxynitrite and
nitroxyl anion.
A role for
nitroxyl anion," Journal of Biological Chemistry, vol.
It was suggested that
nitroxyl hydride (HNO) might be generated by archaeal AMO, which could be subsequently oxidized to N[O.sub.2.sup.-] via
nitroxyl oxidoreductase (NxOR) [14].
Meanwhile, TEMPO plays a key role in chemistry and biology as an organic redox catalyst for alcohol, aldehydes, and ketones [16-21] and has shown its catalytic oxidation potential to [H.sub.2][O.sub.2] due to the electrochemical oxidation of stable
nitroxyl radical [22, 23].
They considered a detailed kinetic mechanism that included chemical initiation, reversible
nitroxyl ether decomposition, monomer dimerization, thermal initiation, propagation, the equilibrium between propagating and dormant radicals, alkoxyamine decomposition, rate enhancement, transfer to monomer and dimer, and conventional termination.
It involves various NO-derivatives, such as NO radical,
nitroxyl anion (NO-), peroxynitrite (ONOO-), and S-nitrosothiols (SNOs).
The nitrogen-centered radicals include nitric oxide (NO*) and nitrogen dioxide (N[O.sub.2]*), whereas nitrogen-centered nonradicals are peroxynitrite (ONO[O.sup.-]), alkyl peroxynitrite (ROONO),
nitroxyl anion (N[O.sup.-]), nitrous acid (HN[O.sub.2]), and so on [50].