Probing the Mechanism and Structure-Function Relations in Phenylalanine Hydroxylase

该奖项由无机、生物无机和有机金属化学项目颁发，用于支持加州大学洛杉矶分校的 Mahdi Abu-Omar 教授对紫色杆菌 (cPAH) 中苯丙氨酸羟化酶的研究。 人类同源酶 hPAH 的遗传缺陷是导致苯丙酮尿症的原因。 本研究涉及：1）通过测量18O动力学同位素效应确定PAH催化反应的限速步骤； 2）通过动力学和光谱方法捕获和表征PAH中参与氧活化的中间体； 3）通过酶的位点特异性突变体了解活性位点结构和底物选择性的起源； 4）通过创建和探索由hPAH调节结构域和cPAH催化结构域组成的新PAH嵌合体的反应性来建立结构-功能关系。将研究重要酶苯丙氨酸羟化酶的功能，苯丙氨酸羟化酶合成必需氨基酸酪氨酸，酪氨酸进一步代谢为重要的神经递质。 这项工作将集中于氧如何在其含铁活性位点被激活。

This award by the Inorganic, Bioinorganic and Organometallic Chemistry program supports research by Professor Mahdi Abu-Omar of the University of California at Los Angeles to study the enzyme, phenylalanine hydroxylase from chromobacterium violaceum (cPAH). A genetic deficiency in the homologous human enzyme, hPAH, is responsible for the disease phenylketonuria. This research involves: 1) determining the rate-limiting step in the catalytic reaction of PAH by measuring 18O kinetic isotope effects; 2) trapping and characterizing intermediates involved in oxygen activation in PAH by kinetic and spectroscopic methods; 3) understanding the active site architecture and the origin of the substrate selectivity through site-specific mutants of the enzyme; and 4) establishing structure-function relationships by creating and exploring the reactivity of new PAH chimera composed of the regulatory domain of hPAH and the catalytic domain of cPAH.The function of an important enzyme, phenylalanine hydroxylase, which synthesizes an essential amino acid, tyrosine that is further metabolized to important neurotransmitters will be studied. The work will focus on how oxygen is activated at its iron-containing active site.