L-2-amino-3-oxobutanoate

• 分子结构分类: 有机化合物 - 有机酸及其衍生物 - 羧酸及其衍生物
• 英文名称: L-2-amino-3-oxobutanoate
• 英文别名: (2S)-2-azaniumyl-3-oxobutanoate
• 化学式: C4H7NO3
• 分子量: 117.1
• InChiKey: SAUCHDKDCUROAO-VKHMYHEASA-N

计算性质

• 辛醇/水分配系数(LogP)：
  -3.4
• 重原子数：
  8
• 可旋转键数：
  2
• 环数：
  0.0
• sp3杂化的碳原子比例：
  0.5
• 拓扑面积：
  80.4
• 氢给体数：
  2
• 氢受体数：
  4

反应信息

• 作为反应物：
  描述：

  L-2-amino-3-oxobutanoate 、 氢(+1)阳离子 生成 Ammonioacetone 、 二氧化碳
  参考文献：
  名称：

  Highly Thermostable L-Threonine Dehydrogenase from the Hyperthermophilic Archaeon Thermococcus kodakaraensis

  摘要：

  l-苏氨酸脱氢酶是l-苏氨酸代谢的关键酶，催化NAD+依赖性l-苏氨酸向2-氨基-3-酮丁酸的转化，后者非酶性脱羧生成氨基丙酮。对超嗜热古菌Thermococcus kodakaraensis的基因组序列进行搜索后发现，存在与古细菌和细菌l-苏氨酸脱氢酶基因密切相关的同源物（TK0916）。在大肠杆菌中表达TK0916基因产物并进行纯化和表征后发现，该基因实际上编码一种具有高水平的l-苏氨酸脱氢酶活性的蛋白质（7.26 U mg-1）。该酶在pH 12和90°C时表现出最高的活性。在50°C时，l-苏氨酸和NAD+的Km值分别为1.6 mM和0.028 mM。酶的活性取决于二价阳离子。在85°C时，酶的半衰期超过2小时，在沸水中为24分钟。这是迄今为止报道的最热稳定的苏氨酸脱氢酶，在最高pH（12）下表现出最佳活性。这是首次报道对Thermococcus属的TDH进行表征。

  DOI：

  10.1093/jb/mvp051
• 作为产物：
  描述：

  (2R)-N-[3-(2-acetylsulfanylethylimino)-3-oxidopropyl]-4-[[[(2R,3S,4R,5R)-5-(6-aminopurin-9-yl)-4-hydroxy-3-phosphonatooxyoxolan-2-yl]methoxy-hydroxyphosphoryl]oxy-hydroxyphosphoryl]oxy-2-hydroxy-3,3-dimethylbutanimidate 、 聚甘氨酸 生成 L-2-amino-3-oxobutanoate 、 coenzyme A
  参考文献：
  名称：

  大肠杆菌的2-氨基-3-酮丁酸CoA连接酶的三维结构与PLP底物中间体复合：推断的反应机理。

  摘要：

  2-氨基-3-酮丁酸CoA连接酶（KBL，EC 2.3.1.29）是一种依赖吡al醛的磷酸酶（PLP），可催化苏氨酸在主要代谢降解途径上的第二步反应。它与苏氨酸脱氢酶协同作用，将辅酶CoA参与的后一种酶的苏氨酸脱氢产物2-氨基-3-酮丁酸酯转化为甘氨酸和乙酰辅酶A。该酶在进化过程中已被很好地保守，在大肠杆菌和人类酶之间具有54％的氨基酸序列同一性。我们介绍了在2.0 A分辨率下确定的大肠杆菌KBL的三维结构。KBL属于PLP依赖酶的alpha家族，其原型成员是天冬氨酸转氨酶。它最接近的结构同源物是大肠杆菌8-氨基-7-氧代壬酸合酶。像alpha家族的许多其他成员一样，KBL的功能形式是二聚体，并且在晶体的不对称单元中发现了一个这样的二聚体。每个二聚体有两个活动位点，位于二聚体界面。两种单体均向每个活性/底物结合位点贡献侧链。电子密度图表明2-氨基-3-酮丁酸酯和PLP（一种外部醛亚胺）的席

  DOI：

  10.1021/bi002204y

文献信息

• L-Threonine dehydrogenase from the hyperthermophilic archaeon Pyrococcus horikoshii OT3: gene cloning and enzymatic characterization
  作者：Yasuhiro Shimizu、Haruhiko Sakuraba、Ryushi Kawakami、Shuichiro Goda、Yutaka Kawarabayasi、Toshihisa Ohshima

  DOI：10.1007/s00792-005-0447-2

  日期：2005.8

  A gene encoding the L-threonine dehydrogenase homologue has been identified in a hyperthermophlic archaeon Pyrococcus horikoshii OT3 via genome sequencing. The gene was cloned and expressed in Escherichia coli. The purified enzyme from the recombinant E. coli was extremely thermostable; the activity was not lost after incubation at 100 degrees C for 20 min. The enzyme ( molecular mass: 192 kDa) is composed of a tetrameric structure with a type of subunit ( 41 kDa). The enzyme is specific for NAD and utilizes L-threonine, L-serine and DL-threo-3-phenylserine as the substrate. The enzyme required divalent cations such as Zn2+, Mn2+ and Co2+ for the activity, and contained one zinc ion/subunit. The K-m values for L-threonine and NAD at 50 degrees C were 0.20 mM and 0.024 mM, respectively. Kinetic analyses indicated that the L-threonine oxidation reaction proceeds via a random mechanism with regard to the binding of L-threonine and NAD. The enzyme showed pro-R stereospecificity for hydrogen transfer at the C4 position of the nicotinamide moiety of NADH. This is the first description of the characteristics of an L-threonine dehydrogenase from the archaea domain.
• Kinetic study of thermostable L-threonine dehydrogenase from an archaeon Pyrococcus horikoshii
  作者：Noriko Higashi、Harumi Fukada、Kazuhiko Ishikawa

  DOI：10.1263/jbb.99.175

  日期：2005.2

  In the genome data base of the hyperthermophilic archaeon Pyrococcus horikoshii, an open reading frame with sequence homology to a gene encoding alcohol dehydrogenase was found. It was demonstrated that the encoded enzyme was a thermostable L-threonine dehydrogenase which can oxidize the hydroxy alkyl residue of L-threonine associated with the reduction of NAD(+) or NADP'. This enzyme is a member of the zinc-containing L-threonine dehydrogenase family. One enzyme molecule contained one zinc atom, and this metal was considered to contribute to the hyperthermostablility of the enzyme. The reaction of the enzyme proceeded via a sequential mechanism. The Michaelis constants (K-m) for L-threonine and NAD(+) were 0.013 and 0.010 mM, respectively, and the maximum reaction rate (V-max) was 1.75 mmol NADH formed/min/mg-protein at 65 degrees C. The Km values for both L-threonine and NADP(+) were larger than those for L-threonine and NAD(+) with a similar V-max. value. These results indicate that the enzyme has lower affinity to NADP(+) than to NAD(+), and the binding affinity for L-threonine depends on the coenzymes.
• Production and characterization of a thermostable L-threonine dehydrogenase from the hyperthermophilic archaeon<i>Pyrococcus furiosus</i>
  作者：Ronnie Machielsen、John van der Oost

  DOI：10.1111/j.1742-4658.2006.05290.x

  日期：2006.6

  The gene encoding a threonine dehydrogenase (TDH) has been identified in the hyperthermophilic archaeon Pyrococcus furiosus. The Pf‐TDH protein has been functionally produced in Escherichia coli and purified to homogeneity. The enzyme has a tetrameric conformation with a molecular mass of ≈ 155 kDa. The catalytic activity of the enzyme increases up to 100 °C, and a half‐life of 11 min at this temperature indicates its thermostability. The enzyme is specific for NAD(H), and maximal specific activities were detected with l‐threonine (10.3 U·mg−1) and acetoin (3.9 U·mg−1) in the oxidative and reductive reactions, respectively. Pf‐TDH also utilizes l‐serine and d‐threonine as substrate, but could not oxidize other l‐amino acids. The enzyme requires bivalent cations such as Zn2+ and Co2+ for activity and contains at least one zinc atom per subunit. Km values for l‐threonine and NAD+ at 70 °C were 1.5 mm and 0.055 mm, respectively.
• Crystallization and preliminary X-ray diffraction analysis of<scp>L</scp>-threonine dehydrogenase (TDH) from the hyperthermophilic archaeon<i>Thermococcus kodakaraensis</i>
  作者：A. Bowyer、H. Mikolajek、J. N. Wright、A. Coker、P. T. Erskine、J. B. Cooper、Q. Bashir、N. Rashid、F. Jamil、M. Akhtar

  DOI：10.1107/s1744309108025384

  日期：2008.9.1

  The enzyme L-threonine dehydrogenase catalyses the NAD(+)-dependent conversion of L-threonine to 2-amino-3-ketobutyrate, which is the first reaction of a two-step biochemical pathway involved in the metabolism of threonine to glycine. Here, the crystallization and preliminary crystallographic analysis of L-threonine dehydrogenase (Tk-TDH) from the hyperthermophilic organism Thermococcus kodakaraensis KOD1 is reported. This threonine dehydrogenase consists of 350 amino acids, with a molecular weight of 38 kDa, and was prepared using an Escherichia coli expression system. The purified native protein was crystallized using the hanging-drop vapour-diffusion method and crystals grew in the tetragonal space group P4(3)2(1)2, with unit-cell parameters a = b = 124.5, c = 271.1 angstrom. Diffraction data were collected to 2.6 angstrom resolution and preliminary analysis indicates that there are four molecules in the asymmetric unit of the crystal.
• Epperly B.R.; Dekker E.E., J Biol Chem, 1991, 0021-9258, 6086-92
  作者：Epperly B.R.、Dekker E.E.

  DOI：——

  日期：——