Nitric oxide is inactivated by the bacterial pigment pyocyanin

Biochem J. 1990 Mar 15;266(3):921-3.


Pyocyanin is a phenazine pigment produced by the bacterium Pseudomonas aeruginosa and found in human lung secretions. Micromolar concentrations of pyocyanin inhibited the bioactivity of endothelium-derived relaxing factor (EDRF) generated from bovine pulmonary-artery endothelium in response to bradykinin. This inhibition was reversed by perfusing the EDRF-bioassay system with pyocyanin-free buffer for 15 min, but persisted in the presence of superoxide dismutase (20 units/ml). When nitric oxide, the major component of EDRF, was passed into an aqueous solution of pyocyanin in the absence of O2, a rapid colour change occurred from blue to pink; m.s. analysis of the products showed that the pyocyanin had been converted into a nitrosylated species.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bradykinin / pharmacology
  • Cell Line
  • Endothelial Growth Factors
  • Endothelium / drug effects
  • Endothelium / metabolism
  • Growth Substances / pharmacology
  • Male
  • Nitric Oxide / antagonists & inhibitors*
  • Nitric Oxide / metabolism
  • Phenazines / pharmacology*
  • Pyocyanine / pharmacology*
  • Rats
  • Rats, Inbred Strains


  • Endothelial Growth Factors
  • Growth Substances
  • Phenazines
  • Nitric Oxide
  • Pyocyanine
  • Bradykinin