Oxidation of nitric oxide by oxygen in biological systems monitored by porphyrinic sensor

A porphyrinic sensor was used to monitor the reaction of nitric oxide (NO) with oxygen. In the absence of biological material, the reaction rate is independent of the initial concentration of NO (zero order) and depends only on O2 concentration (first order). At physiologic concentration of NO and O2, the half-life of nitric oxide is in order of minutes and decreased to seconds only in the presence of biological material (intact cells).