nitric oxide (NO, endothelium derived relaxation factor {EDRF})

From Aaushi
Jump to navigation Jump to search

Function

  • a colorless gas & a free radical
  • nitric oxide reacts rapidly with oxygen to form nitrogen oxides, which ultimately convert to nitrite (NO2-) & nitrate (NO3-)
NO +  O2  ->  NO2  +  N2O3  +  N2O2   ->  NO2-  +  NO3-
  • nitric oxide is a gaseous mediator of cell to cell communication & a potent vasodilator
    • insufficient NO may contribute to hypertension
  • nitric oxide activates soluble guanylate cyclase
    • it mediates penile erection.
  • in the immune system, macrophages use nitric oxide as a cytotoxic agent.
  • free nitric oxide in the circulation is rapidly reduced by Fe+2 of hemoglobin
  • nitric oxide covalently binds to Cyst of proteins resulting in S-nitrosylated derivatives[2][3]
    • S-nitrosylation is reversible
    • targets of S-nitrosylation include:
      • Na+ pump
      • Na+ K+ ATPase
      • alpha tubulin
      • NMDA receptor
      • GAPDH*

* S-nitrosylation of GAPDH triggers nuclear translocation via binding to Siah1. Nitrosylated GAPDH stabilizes Siah1, an E3-ubiquitin ligage that mediates proteolysis of nuclear proteins leading to apoptosis

Expression

nitric oxide is formed from L-arginine by:

Laboratory

More general terms

Additional terms

Component of

References

  1. Stedman's Medical Dictionary 27th ed, Williams & Wilkins, Baltimore, 1999
  2. 2.0 2.1 Tidball J, 9th Annual UCLA Research Conference on Aging, June 17, 2004 (conference speaker)
  3. 3.0 3.1 Sedlak TW, Snyder SH. Messenger molecules and cell death: therapeutic implications. JAMA. 2006 Jan 4;295(1):81-9. PMID: https://www.ncbi.nlm.nih.gov/pubmed/16391220

Database