title: Phenylalanine binding is linked to dimerization of the regulatory domain of phenylalanine hydroxylase.
abstract: Analytical ultracentrifugation has been used to analyze the oligomeric structure of the isolated regulatory domain of phenylalanine hydroxylase. The protein exhibits a monomer-dimer equilibrium with a dissociation constant of ~46 μM; this value is unaffected by the removal of the 24 N-terminal residues or by phosphorylation of Ser16. In contrast, phenylalanine binding (Kd = 8 μM) stabilizes the dimer. These results suggest that dimerization of the regulatory domain of phenylalanine hydroxylase is linked to allosteric activation of the enzyme.
authors.affiliation: Department of Biochemistry, University of Texas Health Science Center at San Antonio , San Antonio, Texas 78229, United States.
authors.forename: Shengnan
authors.initials: S
authors.lastname: Zhang
authors.forename: Kenneth M
authors.initials: KM
authors.lastname: Roberts
authors.forename: Paul F
authors.initials: PF
authors.lastname: Fitzpatrick
mesh_terms: D019281:Dimerization; D010649:Phenylalanine / Q000737:chemistry*; D010651:Phenylalanine Hydroxylase / Q000737:chemistry*; D010766:Phosphorylation; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D012694:Serine / Q000737:chemistry
chemical_list: D012694:Serine; D010649:Phenylalanine; D010651:Phenylalanine Hydroxylase