title: Dictyostelium phenylalanine hydroxylase is activated by its substrate phenylalanine.
abstract: We have studied the regulatory function of Dictyostelium discoideum Ax2 phenylalanine hydroxylase (dicPAH) via characterization of domain structures. Including the full-length protein, partial proteins truncated in regulatory, tetramerization, or both, were prepared from Escherichia coli as his-tag proteins and examined for oligomeric status and catalytic parameters for phenylalanine. The proteins were also expressed extrachromosomally in the dicPAH knockout strain to examine their in vivo compatibility. The results suggest that phenylalanine activates dicPAH, which is functional in vivo as a tetramer, although cooperativity was not observed. In addition, the results of kinetic study suggest that the regulatory domain of dicPAH may play a role different from that of the domain in mammalian PAH.
authors.affiliation: FIRST Research Group, School of Biological Sciences, Inje University, Kimhae 621-749, Republic of Korea.
authors.forename: Hye-Lim
authors.initials: HL
authors.lastname: Kim
authors.forename: Mi-Bee
authors.initials: MB
authors.lastname: Park
authors.forename: Yumin
authors.initials: Y
authors.lastname: Kim
authors.forename: Yun Gyeong
authors.initials: YG
authors.lastname: Yang
authors.forename: Soo-Woong
authors.initials: SW
authors.lastname: Lee
authors.forename: Ningning
authors.initials: N
authors.lastname: Zhuang
authors.forename: Kon Ho
authors.initials: KH
authors.lastname: Lee
authors.forename: Young Shik
authors.initials: YS
authors.lastname: Park
mesh_terms: D055162:Biocatalysis; D004023:Dictyostelium / Q000201:enzymology*; D004789:Enzyme Activation / Q000187:drug effects; D004795:Enzyme Stability; D007700:Kinetics; D010649:Phenylalanine / Q000378:metabolism* / Q000494:pharmacology*; D010651:Phenylalanine Hydroxylase / Q000737:chemistry* / Q000378:metabolism*; D011485:Protein Binding; D055503:Protein Multimerization; D017434:Protein Structure, Tertiary
chemical_list: D010649:Phenylalanine; D010651:Phenylalanine Hydroxylase