Lunte C E, Kissinger P T
Anal Biochem. 1984 Jun;139(2):468-73. doi: 10.1016/0003-2697(84)90036-8.
An assay method is presented for the determination of phenylalanine hydroxylase activity in biological samples. The procedure is rapid and requires little sample. Multiple components of the enzyme system are determined and therefore serve as internal checks of the assay system. Liquid chromatography/electrochemistry is employed to follow the oxidation of the tetrahydropterin cofactor to the dihydropterin and to follow the formation of tyrosine. The KM and Vmax values of both phenylalanine and 6-methyl-5,6,7,8-tetrahydropterin were determined for mouse liver phenylalanine hydroxylase. Determination of the stoichiometry of the reaction showed that 1 mol of dihydropterin and 1 mol of tyrosine are formed per mole of tetrahydropterin that is oxidized. The reaction rate was linear for several minutes and over a wide range of enzyme (protein) concentrations.
本文介绍了一种用于测定生物样品中苯丙氨酸羟化酶活性的检测方法。该方法快速且所需样品量少。可测定酶系统的多个组分，因此可作为检测系统的内部对照。采用液相色谱/电化学法跟踪四氢生物蝶呤辅因子氧化为二氢生物蝶呤的过程以及酪氨酸的形成过程。测定了小鼠肝脏苯丙氨酸羟化酶对苯丙氨酸和6-甲基-5,6,7,8-四氢生物蝶呤的米氏常数（KM）和最大反应速率（Vmax）。反应化学计量比的测定表明，每氧化1摩尔四氢生物蝶呤会形成1摩尔二氢生物蝶呤和1摩尔酪氨酸。反应速率在几分钟内以及很宽的酶（蛋白质）浓度范围内呈线性。
