酪氨酸羟化酶结合四氢生物蝶呤辅因子与负协同,如图所示的动力学分析和表面等离子体共振检测。

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Flatmark T,阿尔玛B, Knappskog点,Berge SV, Svebak RM, Chehin R,蒙加一个,马丁内斯

酪氨酸羟化酶结合四氢生物蝶呤辅因子与负协同,如图所示的动力学分析和表面等离子体共振检测。

欧元。1999 262年6月;(3):840 - 9。

PubMed ID

10411647 (在PubMed

]

文摘

动力学的研究四聚物的重组体人酪氨酸羟化酶同种型1 (hTH1)显示属性到目前为止没有报告这种酶。首先,与自然代数余子式(6 r) -Lerythro-5, 6, 7, 8-tetrahydrobiopterin (H4biopterin)时间观察(破裂)的酶活性变化,半场约20年代动力学瞬态。其次,nonhyperbolic饱和行为被发现的H4biopterin明显负协同(0.39 < h < 0.58;[S] 0.5 = 24 + / - 4 microM)。Ser40通过蛋白激酶磷酸化,H4biopterin的亲和力增加(0.5 [S] = 11 + / - 2 microM)和负协同放大(h = 0.27 + / - 0.03)。二聚c端缺失突变体(delta473 - 528) hTH1还显示负协同H4biopterin绑定(h = 0.4)。协调与辅因子类似物6-methyl-5没有被观察到,6、7,8-tetrahydropterin (h = 0.9 + / - 0.1;公里= 62.7 + / - 5.7 microM)和3-methyl-5, 6, 7, 8-tetrahydropterin (H43-methyl-pterin) (h = 1.0 + / - 0.1;公里= 687 + / - 50 microM)。在1毫米H43-methyl-pterin面前,作为竞争的代数余子式模拟BH4,双曲饱和曲线也发现H4biopterin (h = 1.0),从而确认真正的动力学性质-协同。 This cooperativity was confirmed by real-time biospecific interaction analysis by surface plasmon resonance detection. The equilibrium binding of H4biopterin to the immobilized iron-free apoenzyme results in a saturable positive resonance unit (DeltaRU) response with negative cooperativity (h = 0.52-0.56). Infrared spectroscopic studies revealed a reduced thermal stability both of the apo-and the holo-hTH1 on binding of H4biopterin and Lerythro-dihydrobiopterin (H2biopterin). Moreover, the ligand-bound forms of the enzyme also showed a decreased resistance to limited tryptic proteolysis. These findings indicate that the binding of H4biopterin at the active site induces a destabilizing conformational change in the enzyme which could be related to the observed negative cooperativity. Thus, our studies provide new insight into the regulation of TH by the concentration of H4biopterin which may have significant implications for the physiological regulation of catecholamine biosynthesis in neuroendocrine cells.

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药物靶点

药物	目标	类	生物	药理作用	行动
Sapropterin	酪氨酸3-monooxygenase	蛋白质	人类	是的	代数余子式	细节