(4aS,6R)-4a-hydroxy-L-erythro-5,6,7,8-tetrahydrobiopterin

Three steps

• N-docosanoylglycineReach from here →
  1. (6R)-L-erythro-5,6,7,8-tetrahydrobiopterin + L-tryptophan + O2 = 5-hydroxy-L-tryptophan + (4aS,6R)-4a-hydroxy-L-erythro-5,6,7,8-tetrahydrobiopterin
  2. transport of glycine and tryptophan (cytosol to extracellular)
  3. docosanoyl-CoA + glycine = N-docosanoylglycine + CoA + H(+)

  Catalysed by TPH1, TPH2, SLC7A5, BAATextracellular space, cytosol

• N-hexacosanoylglycineReach from here →
  1. (6R)-L-erythro-5,6,7,8-tetrahydrobiopterin + L-tryptophan + O2 = 5-hydroxy-L-tryptophan + (4aS,6R)-4a-hydroxy-L-erythro-5,6,7,8-tetrahydrobiopterin
  2. transport of glycine and tryptophan (cytosol to extracellular)
  3. hexacosanoyl-CoA + glycine = N-hexacosanoylglycine + CoA + H(+)

  Catalysed by TPH1, TPH2, SLC7A5, BAATextracellular space, cytosol

• an N(2)-acyl-L-glutamineReach from here →
  1. (6R)-L-erythro-5,6,7,8-tetrahydrobiopterin + L-tryptophan + O2 = 5-hydroxy-L-tryptophan + (4aS,6R)-4a-hydroxy-L-erythro-5,6,7,8-tetrahydrobiopterin
  2. transport of glutamine and tryptophan (cytosol to extracellular)
  3. an acyl-CoA + L-glutamine = an N(2)-acyl-L-glutamine + CoA + H(+)

  Catalysed by TPH1, TPH2, SLC7A5, GLYATL1B and 1 moreextracellular space, cytosol