SYNTHESIS AND RELEASE OF BIOGENIC AMINES

这些研究主要集中在酪氨酸的调节特性上。 羟基酶、色氨酸羟基酶及其辅因子 四氢生物蝶呤(BH4)在生物合成和释放中的作用 大脑中的儿茶酚胺和5-羟色胺。 我们已经鉴定出人类色氨酸羟基酶的两种亚型 M RNA和蛋白水平。人类脑干只表达其中的一种 而松果体两者都有。初步数据显示，有 负责两种异构体的两个启动子。这些结果提供了 色氨酸调节机制的分析线索 转录水平的羟基酶。 通过使用表面等离子体共振光谱，我们已经证明 被磷酸化的色氨酸羟基酶之间的结合 CAMP依赖的蛋白激酶和14-3-3蛋白。14-3-3不仅 激活色氨酸羟解酶，但也保护它免受 去磷酸化。 诱变研究表明，人脑中的主要部位 被cAMP依赖蛋白磷酸化的色氨酸羟化酶 激酶是丝氨酸-58，而丝氨酸-260是推测的位置 与14-3-3相互作用，只有很小程度的磷酸化。 此外，我们还检测到了 4A-羟基四氢生物蝶呤在色氨酸羟化反应中的作用 重组色氨酸羟基酶。色氨酸的活性 在蝶呤存在的情况下羟基酶增加2倍 4A-甲醇胺脱水酶，是一种将 羟基四氢蝶呤为二氢蝶呤衍生物。

These studies have focused on the regulatory properties of tyrosine hydroxylase, tryptophan hydroxylase and their cofactor tetrahydrobiopterin (BH4) in the biosynthesis and release of catecholamine and serotonin in the brain. We have identified two isoforms of human tryptophan hydroxylase on both mRNA and protein level. Human brainstem expresses only one of them while pineal gland has both. Preliminary data indicate that there are two promoters responsible for the two isoforms. These results provide clues for the analysis of the mechanism of regulation of tryptophan hydroxylase at the transcription level. By using surface plasmon resonance spectroscopy, we have demonstrated the binding between tryptophan hydroxylase that was phosphorylated by cAMP-dependent protein kinase and 14-3-3 proteins. 14-3-3 not only activates the tryptophan hydroxylase, but also protects it from dephosphorylation. Mutagenesis studies indicate that the major site in human brain tryptophan hydroxylase that is phosphorylated by cAMP-dependent protein kinase is serine-58 while serine-260, which is the site that is supposed to interact with 14-3-3, is only phosphorylated to a small extent. In addition, we have detected the formation of 4a-hydroxytetrahydrobiopterin during the hydroxylation of tryptophan by the recombinant tryptophan hydroxylase. The activity of tryptophan hydroxylase is increased by 2-fold in the presence of pterin 4a-carbinolamine dehydratase, the enzyme that converts the hydroxytetrahydropterin to the dihydropterin derivative.