AAAH

links: Enzyme reference: 4-24-2021

AAAH #

• Tetramers coordinated by an Iron, which must be in ferrous (II) to carry out catalysis. However, they may be isolated to contain (high-spin!?) ferric iron. Its reduction is mediated by Tetrahydrobiopterin whereby it becomes qBH2 or something.
• A major subfamily is the biopterin-dependent aromatic amino acid hydroxylase: (really just uses Tetrahydrobiopterin)
  • Phenylalanine Hydroxylase
  • Tyrosine Hydroxylase
    • Located mainly in the cell bodies of neurons. In the cytoplasm.
    • Copper-containing, unlike tryptophan. Together with the fact that copper can displace iron, loss of TH activity is less worrisome during Iron “deficiency”
      • I think it may be dependent on ceruloplasmin activity or something. I just heard all this on GE podcast
  • Tryptophan Hydroxylase