4a-hydroxypterin | 83387-39-7

• 分子结构分类: 有机化合物 - 有机杂环化合物 - 咪唑并嘧啶类
• 英文名称: 4a-hydroxypterin
• 英文别名: 2-Amino-4a-hydroxy-6-methyl-3,5,6,7-tetrahydropteridin-4-one
• CAS: 83387-39-7
• 化学式: C₇H₁₁N₅O₂
• 分子量: 197.197
• InChiKey: LRQOEVGTDREQQD-UHFFFAOYSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  -2.4
• 重原子数：
  14
• 可旋转键数：
  0
• 环数：
  2.0
• sp3杂化的碳原子比例：
  0.57
• 拓扑面积：
  112
• 氢给体数：
  4
• 氢受体数：
  4

反应信息

• 作为产物：
  描述：

  2-氨基-6-甲基-5,6,7,8-四氢蝶啶-4(1H)-酮 在 tyrosine hydroxylase 作用下， 生成 4a-hydroxypterin
  参考文献：
  名称：

  酪氨酸羟化酶一氧化氮复合物中氨基酸和四氢蝶呤结合的脉冲 EPR 研究：氧反应复合物形成过程中底物重排的证据

  摘要：

  酪氨酸羟化酶是在神经系统中发现的一种非血红素铁酶，可催化酪氨酸羟基化形成l -3,4-二羟基苯丙氨酸，这是儿茶酚胺神经递质生物合成的限速步骤。催化需要结合三种底物：酪氨酸、四氢生物蝶呤和分子氧。我们使用一氧化氮作为 O 2替代物，以S = 3 / 2 {FeNO} 7形式在催化位点处平衡 Fe(II)，适合 EPR 光谱。2然后使用 H 电子自旋回波包络调制来测量特定氘代底物酪氨酸和辅因子 6-甲基四氢蝶呤相对于 {FeNO} 7顺磁中心的磁轴的距离和方向。我们的结果表明，加入酪氨酸的触发以减少从{FeNO水平}的距离的酶的构象变化7中心与最接近的氘核上6,7- 2 H-6-methyltetrahydropterin从> 5.9埃至4.4±0.2的. 相反，向用 3,5- 2 H-酪氨酸处理的酶样品添加 6-甲基四氢蝶呤导致S = 3 / 2 , {FeNO} 7的磁轴重新定向以氘代底物

  DOI：

  10.1021/bi4010914

文献信息

• Characterization of Unstable Products of Flavin- and Pterin-Dependent Enzymes by Continuous-Flow Mass Spectrometry
  作者：Kenneth M. Roberts、José R. Tormos、Paul F. Fitzpatrick

  DOI：10.1021/bi500267c

  日期：2014.4.29

  Continuous-flow mass spectrometry (CFMS) was used to monitor the products formed during the initial 2 0.25-20 s of the reactions catalyzed by the flavoprotein N-acetylpolyamine oxidase (PAO) and the pterin-dependent enzymes phenylalanine hydroxylase (PheH) and tyrosine hydroxylase (TyrH). N,N'-Dibenzyl-1,4-diaminobutane (DBDB) is a substrate for PAO for which amine oxidation is rate-limiting. CFMS of the reaction showed formation of an initial imine due to oxidation of an exo-carbon-nitrogen bond. Nonenzymatic hydrolysis of the imine formed benzaldehyde and N-benzyl-1,4-diaminobutane; the subsequent oxidation by PAO of the latter to an additional imine could also be followed. Measurement of the deuterium kinetic isotope effect on DBDB oxidation by CFMS yielded a value of 7.6 +/- 0.3, in good agreement with a value of 6.7 +/- 0.6 from steady-state kinetic analyses. In the PheH reaction, the transient formation of the 4a-hydroxypterin product was readily detected; tandem mass spectrometry confirmed attachment of the oxygen to C(4a). With wild-type TyrH, the 4a-hydroxypterin was also the product. In contrast, no product other than a dihydropterin could be detected in the reaction of the mutant protein E332A TyrH.