• (6R)-L-erythro-5,6,7,8-tetrahydrobiopterin + L-tryptophan + oxygen → (6R)-4a-hydroxy-tetrahydrobiopterin + 4-hydroxy-L-tryptophan (R00908)
  • Overexpression
    • Plasmid
      • Escherichia coli PP02
      • Escherichia coli PP03
      • Escherichia coli PP04
      • Escherichia coli PP05
      • Escherichia coli PP06
• 4-hydroxy-L-tryptophan + H⁺ → 4-hydroxytryptamine + CO₂ (R11678)
  • Overexpression
    • Plasmid
      • Escherichia coli PP04
      • Escherichia coli PP05
      • Escherichia coli PP06