RT Book, Section A1 Erlandsen, Heidi A1 Stevens, Raymond C. A2 Valle, David L. A2 Antonarakis, Stylianos A2 Ballabio, Andrea A2 Beaudet, Arthur L. A2 Mitchell, Grant A. SR Print(0) ID 1181421745 T1 Structural Studies of Phenylalanine Hydroxylase Enzyme T2 The Online Metabolic and Molecular Bases of Inherited Disease YR 2019 FD 2019 PB McGraw-Hill Education PP New York, NY SN 9780071459969 LK ommbid.mhmedical.com/content.aspx?aid=1181421745 RD 2024/10/03 AB Recombinant human (liver) phenylalanine hydroxylase (PheOH, phenylalanine 4-monooxygenase, EC 1.14.16.1) is reported to exist in solution as a pH-dependent equilibrium between homotetramers and homodimers (Martinez et al,34). The molecular weight of one subunit is approximately 50 kDa (between 50 and 53 kDa). It has an absolute requirement for ferrous iron to be active, and uses the cofactors BH4 and O2 to perform the hydroxylation reaction. PheOH, like the two other aromatic amino acid hydroxylases tyrosine hydroxylase (TyrOH, tyrosine 3-monooxygenase, EC 1.14.16.2) and tryptophan hydroxylase (TrpOH, tryptophan 5-monooxygenase, EC 1.14.16.4), consists of three domains: the regulatory domain (residues 1-142), the catalytic domain (residues 143-410), and a short tetramerization domain (residues 411-452).