Novel nitric oxide-liberating heme proteins from the saliva of bloodsucking insects.

The spectroscopic (UV-visible, IR, RR, MCD, Mössbauer, EPR), crystallographic, kinetic, and redox investigations that have been carried out on model hemes, hemoglobin, myoglobin, cytochrome a3 of cytochrome oxidase, horseradish peroxidase, prostaglandin H synthase, cytochromes P450, chloroperoxidase, and so forth have shown us the unique properties of heme-NO centers, as summarized above. However, in none of these cases is the Fe(III)NO complex of any known physiological importance. The nitrophorins of R. prolixus [59] (and Cimex lectularius [80]) are thus far unique in this respect. It is likely that further investigations of the roles of NO in biological systems will discover additional interesting involvements of heme proteins in these roles.