Nitric oxide: Chemistry and bioactivity in animal and plant cells

Abstract In mammals, nitric oxide (NO) is a reactive free radical involved in diverse physiological functions. NO and its redox-related forms NO + and NO − react with di(oxygen) and its derivatives, with metalloproteins and thiol-containing proteins. NO-mediated nitrosation of proteins represents an important cellular regulatory mechanism. Biosynthesis of NOis catalysed by nitric oxide synthase (NOS). Three isoenzymes representing distinct gene products have been identified: the inducible NOS isoform, the constitutive neuronal and endothelial isoforms. Inducible and constitutive NOSs have the same structural features, but their activities differ in their dependence to calcium and the rate o…