Thermodynamic considerations on the formation of reactive species from hypochlorite, superoxide and nitrogen monoxide. Could nitrosyl chloride be produced by neutrophils and macrophages?

Hypohalous acids are poor one-electron oxidizing agents, such that reactions with hydrogen peroxide to yield radical species are not feasible. However, the oxidation of superoxide by hypohalous acids can be a source of hydroxyl or haline radicals. The oxidation of nitrogen monoxide by hypochlorous acid is favourable, but in all likelihood cannot compete with the diffusion-controlled reaction with superoxide to yield peroxynitrite. The reaction of the latter with hypochlorous acid may lead to nitrosyl chloride, a strongly oxidizing agent [Eo'(NOCl/NO., Cl) = 1.0 V] that is capable of nitrosylating organic compounds and thereby generating mutagens or promutagens.