Tetrahydrobiopterin in nitric oxide synthase

IUBMB Life. 2013 Apr;65(4):358-65. doi: 10.1002/iub.1136. Epub 2013 Feb 26.


Nitric oxide synthase (NOS) is a critical enzyme for the production of the messenger molecule nitric oxide (NO) from L-arginine. NOS enzymes require tetrahydrobiopterin as a cofactor for NO synthesis. Besides being one of the few enzymes to use this cofactor, the role of tetrahydrobiopterin in NOS catalytic mechanism is different from other enzymes: during the catalytic cycle of NOS, tetrahydrobiopterin forms a radical species that is again reduced, thus effectively regenerating after each NO synthesis cycle. In this review, we summarize our current knowledge about the role of tetrahydrobiopterin in the structure, function, and catalytic mechanism of NOS enzymes.

Publication types

  • Review

MeSH terms

  • Amino Acid Oxidoreductases / chemistry
  • Arginine / chemistry
  • Arginine / metabolism*
  • Biopterin / analogs & derivatives
  • Biopterin / chemistry
  • Biopterin / metabolism
  • Catalysis
  • Heme / chemistry
  • Heme / metabolism
  • Nitric Oxide / biosynthesis*
  • Nitric Oxide / metabolism
  • Nitric Oxide Synthase / chemistry
  • Nitric Oxide Synthase / metabolism*


  • Biopterin
  • Nitric Oxide
  • Heme
  • Arginine
  • Nitric Oxide Synthase
  • Amino Acid Oxidoreductases
  • sapropterin