Abscisin II

• 分子结构分类: 有机化合物 - 脂质和类脂质分子 - 异戊烯醇脂质
• 英文名称: Abscisin II
• 英文别名: (2Z,4E)-5-[(1S)-1-hydroxy-2,6,6-trimethyl-4-oxocyclohex-2-en-1-yl]-3-methylpenta-2,4-dienoate
• 化学式: C15H19O4-
• 分子量: 263.31
• InChiKey: JLIDBLDQVAYHNE-YKALOCIXSA-M

计算性质

• 辛醇/水分配系数(LogP)：
  2.3
• 重原子数：
  19
• 可旋转键数：
  2
• 环数：
  1.0
• sp3杂化的碳原子比例：
  0.47
• 拓扑面积：
  77.4
• 氢给体数：
  1
• 氢受体数：
  4

反应信息

• 作为反应物：
  描述：

  Abscisin II 、 UDP-glucose 生成 abscisic acid β-d-glucopyranosyl ester 、 UDP
  参考文献：
  名称：

  Cloning and Characterization of the Abscisic Acid-Specific Glucosyltransferase Gene from Adzuki Bean Seedlings

  摘要：

  已经从许多植物物种中鉴定出了葡萄糖化的脱落酸（ABA）形式，并且已知它们是ABA降解的形式，尽管它们的（生理）作用尚未阐明。ABA葡萄糖转移酶（-GTase）被认为在ABA的葡萄糖化中发挥关键作用。我们从小豆（Vigna angularis）幼苗中获得的UDP-GTase同源物中分离出了一个ABA诱导的GTase基因。推导的氨基酸序列（存取号AB065190）与已知的UDP-GTase同源物相比，显示出30％至44％的同一性。带有谷胱甘肽S-转移酶标签的重组蛋白在大肠杆菌中表达，并以ABA特异性方式显示出酶活性。在柠檬酸和Tris-HCl缓冲液中，在pH 5.0至9.0的宽范围内检测到酶活性，最佳范围在pH 6.0至7.3之间。通过气相色谱/质谱法确定了来自拉丁式ABA和UDP-d-葡萄糖的产物为ABA-GE。重组GTase（rAOG）比（+）-S-ABA和（-）-R-ABA更好地转化2-反式（+）-ABA。虽然GTase轻微地将反-肉桂酸转化为其结合物，但（-）-PA则没有。mRNA水平通过ABA应用或水分胁迫和损伤而增加。我们认为该基因编码ABA特异性GTase，并且其表达受环境胁迫调节。

  DOI：

  10.1104/pp.001784
• 作为产物：
  描述：

  (+)-abscisic acid D-glucopyranosyl ester 、 水 生成 Abscisin II 、 可得然胶 、 氢(+1)阳离子
  参考文献：
  名称：

  Activation of Glucosidase via Stress-Induced Polymerization Rapidly Increases Active Pools of Abscisic Acid

  摘要：

  Abscisic acid (ABA) is a phytohormone critical for plant growth, development, and adaptation to various stress conditions. Plants have to adjust ABA levels constantly to respond to changing physiological and environmental conditions. To date, the mechanisms for fine-tuning ABA levels remain elusive. Here we report that AtBG1, a beta-glucosidase, hydrolyzes glucose-conjugated, biologically inactive ABA to produce active ABA. Loss of AtBG1 causes defective stomatal movement, early germination, abiotic stress-sensitive phenotypes, and lower ABA levels, whereas plants with ectopic AtBG1 accumulate higher ABA levels and display enhanced tolerance to abiotic stress. Dehydration rapidly induces polymerization of AtBG1, resulting in a 4-fold increase in enzymatic activity. Furthermore, diurnal increases in ABA levels are attributable to polymerization-mediated AtBG1 activation. We propose that the activation of inactive ABA pools by polymerized AtBG1 is a mechanism by which plants rapidly adjust ABA levels and respond to changing environmental cues.

  DOI：

  10.1016/j.cell.2006.07.034

文献信息

• Aldehyde Oxidase and Xanthine Dehydrogenase in a<i>flacca</i> Tomato Mutant with Deficient Abscisic Acid and Wilty Phenotype1
  作者：Moshe Sagi、Robert Fluhr、S. Herman Lips

  DOI：10.1104/pp.120.2.571

  日期：1999.6.1

  The flacca tomato (Lycopersicon esculentum) mutant displays a wilty phenotype as a result of abscisic acid (ABA) deficiency. The Mo cofactor (MoCo)-containing aldehyde oxidases (AO; EC 1.2.3.1) are thought to play a role in the final oxidation step required for ABA biosynthesis. AO and related MoCo-containing enzymes xanthine dehydrogenase (XDH; EC 1.2.1.37) and nitrate reductase (EC 1.6.6.1) were examined in extracts of the flacca tomato genotype and of wild-type (WT) roots and shoots. The levels of MoCo were found to be similar in both genotypes. No significant XDH or AO (MoCo-containing hydroxylases) activities were detected inflacca leaves; however, the mutant exhibited considerable MoCo-containing hydroxylase activity in the roots, which contained notable amounts of ABA. Native western blots probed with an antibody to MoCo-containing hydroxylases revealed substantial, albeit reduced, levels of cross-reactive protein in the flaccamutant shoots and roots. The ABA xylem-loading rate was significantly lower than that in the WT, indicating that the flacca is also defective in ABA transport to the shoot. Significantly, in vitro sulfurylation with Na2S reactivated preexisting XDH and AO proteins in extracts from flacca, particularly from the shoots, and superinduced the basal-level activity in the WT extracts. The results indicate that in flacca,MoCo-sulfurylase activity is impaired in a tissue-dependent manner.

  flacca番茄（Lycopersicon esculentum）突变体因缺乏脱落酸（ABA）而表现出萎缩表型。钼辅因子（MoCo）含有的醛氧化酶（AO; EC 1.2.3.1）被认为在ABA生物合成所需的最终氧化步骤中发挥作用。AO和相关的MoCo含有的酶黄嘌呤脱氢酶（XDH; EC 1.2.1.37）和硝酸还原酶（EC 1.6.6.1）在flacca番茄基因型和野生型（WT）根和茎的提取物中进行了检查。发现两种基因型中MoCo的水平相似。在flacca的叶片中没有检测到显著的XDH或AO（MoCo含有的羟化酶）活性; 然而，突变体的根部表现出相当数量的MoCo含有的羟化酶活性，其中含有显著的ABA。原生西方印迹用MoCo含有的羟化酶抗体探测显示出flacca突变体的茎和根中存在大量的交叉反应蛋白，尽管水平有所降低。ABA木质部装载速率显著低于WT，表明flacca在ABA运输到茎中也存在缺陷。值得注意的是，在体外用Na2S进行硫酸化可重新激活flacca提取物中预先存在的XDH和AO蛋白质，特别是来自茎的提取物，并超诱导WT提取物中的基础水平活性。结果表明，在flacca中，MoCo-硫酸化酶活性受到组织依赖性的损害。

• The <i>Arabidopsis</i> aldehyde oxidase 3 ( <i>AAO3</i> ) gene product catalyzes the final step in abscisic acid biosynthesis in leaves
  作者：Mitsunori Seo、Anton J. M. Peeters、Hanae Koiwai、Takayuki Oritani、Annie Marion-Poll、Jan A. D. Zeevaart、Maarten Koornneef、Yuji Kamiya、Tomokazu Koshiba

  DOI：10.1073/pnas.220426197

  日期：2000.11.7

  Abscisic acid (ABA) is a plant hormone involved in seed development and germination and in responses to various environmental stresses. The last step of ABA biosynthesis involves oxidation of abscisic aldehyde, and aldehyde oxidase (EC 1.2.3.1 ) is thought to catalyze this reaction. An aldehyde oxidase isoform, AOδ, encoded by AAO3 , one of four Arabidopsis aldehyde oxidase genes ( AAO1 , AAO2 , AAO3 , and AAO4 ), is the most likely candidate for the enzyme, because it can efficiently catalyze the oxidation of abscisic aldehyde to ABA. Here, we report the isolation and characterization of an ABA-deficient Arabidopsis mutant that maps at the AAO3 locus. The mutant exhibits a wilty phenotype in rosette leaves, but seed dormancy is not affected. ABA levels were significantly reduced in the mutant leaves, explaining the wilty phenotype in rosettes, whereas the level in the mutant seeds was less reduced. No AOδ activity could be detected in the rosette leaves of the mutant. Sequence data showed that the mutant contains a G to A substitution in the AAO3 gene. The mutation causes incorrect splicing of the ninth intron of AAO3 mRNA. We thus conclude that the ABA-deficient mutant is impaired in the AAO3 gene and that the gene product, AOδ, is an aldehyde oxidase that catalyzes the last step of ABA biosynthesis in Arabidopsis , specifically in rosette leaves. Other aldehyde oxidases may be involved in ABA biosynthesis in other organs.

  脱落酸（ABA）是一种植物激素，参与种子的发育和萌发以及对各种环境压力的响应。ABA生物合成的最后一步涉及脱落醛的氧化，醛氧化酶（EC 1.2.3.1）被认为催化这个反应。一种醛氧化酶亚型AOδ，由四个阿拉伯芥醛氧化酶基因（AAO1，AAO2，AAO3和AAO4）之一编码的AOδ，是该酶的最可能候选者，因为它可以有效催化脱落醛的氧化为ABA。在这里，我们报道了一个ABA缺陷的阿拉伯芥突变体，在AAO3位点上映射。突变体在莲座叶上表现出枯萎的表型，但种子休眠不受影响。突变体叶片中ABA水平显著降低，解释了莲座叶中枯萎表型，而突变体种子中的水平较少降低。在突变体的莲座叶中无法检测到AOδ活性。序列数据显示，突变体在AAO3基因中含有G到A的突变。该突变导致AAO3 mRNA的第九个内含子的错误剪接。因此，我们得出结论，ABA缺陷突变体在AAO3基因中受损，基因产物AOδ是一种醛氧化酶，催化阿拉伯芥中ABA生物合成的最后一步，特别是在莲座叶中。其他醛氧化酶可能参与其他器官的ABA生物合成。
• Arabidopsis <i>CYP707A</i>s Encode (+)-Abscisic Acid 8′-Hydroxylase, a Key Enzyme in the Oxidative Catabolism of Abscisic Acid
  作者：Shigeki Saito、Nobuhiro Hirai、Chiaki Matsumoto、Hajime Ohigashi、Daisaku Ohta、Kanzo Sakata、Masaharu Mizutani

  DOI：10.1104/pp.103.037614

  日期：2004.4.1

  Abscisic acid (ABA) is involved in a number of critical processes in normal growth and development as well as in adaptive responses to environmental stresses. For correct and accurate actions, a physiologically active ABA level is controlled through fine-tuning of de novo biosynthesis and catabolism. The hydroxylation at the 8′-position of ABA is known as the key step of ABA catabolism, and this reaction is catalyzed by ABA 8′-hydroxylase, a cytochrome P450. Here, we demonstrate CYP707As as the P450 responsible for the 8′-hydroxylation of (+)-ABA. First, all four CYP707A cDNAs were cloned from Arabidopsis and used for the production of the recombinant proteins in insect cells using a baculovirus system. The insect cells expressing CYP707A3 efficiently metabolized (+)-ABA to yield phaseic acid, the isomerized form of 8′-hydroxy-ABA. The microsomes from the insect cells exhibited very strong activity of 8′-hydroxylation of (+)-ABA (K  m = 1.3 μ  m and k  cat = 15 min−1). The solubilized CYP707A3 protein bound (+)-ABA with the binding constant K  s = 3.5 μ  m, but did not bind (−)-ABA. Detailed analyses of the reaction products confirmed that CYP707A3 does not have the isomerization activity of 8′-hydroxy-ABA to phaseic acid. Further experiments revealed that Arabidopsis CYP707A1 and CYP707A4 also encode ABA 8′-hydroxylase. The transcripts of the CYP707A genes increased in response to salt, osmotic, and dehydration stresses as well as ABA. These results establish that the CYP707A family plays a key role in regulating the ABA level through the 8′-hydroxylation of (+)-ABA.

  脱落酸(ABA)参与了许多正常生长和发育过程以及适应环境压力的反应。为了正确和准确地执行这些过程，需要通过精细调节新生合成和分解来控制生理活性的ABA水平。ABA在8′位的羟基化是ABA分解的关键步骤，这个反应由细胞色素P450酶ABA 8′-羟基化酶催化。在这里，我们证明CYP707A是负责8′-羟基化(+)-ABA的P450酶。首先，从拟南芥中克隆了所有四个CYP707A cDNA，并使用杆状病毒系统在昆虫细胞中生产了重组蛋白。表达CYP707A3的昆虫细胞有效地代谢(+)-ABA，产生相位酸，即8′-羟基化ABA的异构体。昆虫细胞的微粒体表现出非常强的8′-羟基化(+)-ABA的活性(Km = 1.3 μm和kcat = 15 min-1)。溶解的CYP707A3蛋白与(+)-ABA结合的结合常数Ks为3.5 μm，但不与(−)-ABA结合。对反应产物的详细分析确认CYP707A3没有8′-羟基化ABA到相位酸的异构化活性。进一步的实验揭示了拟南芥CYP707A1和CYP707A4也编码ABA 8′-羟基化酶。CYP707A基因的转录在盐、渗透和脱水压力以及ABA的作用下增加。这些结果表明，CYP707A家族通过8′-羟基化(+)-ABA在调节ABA水平方面发挥关键作用。

• (+)-Abscisic Acid 8′-Hydroxylase Is a Cytochrome P450 Monooxygenase
  作者：Joan E. Krochko、Garth D. Abrams、Mary K. Loewen、Suzanne R. Abrams、Adrian J. Cutler

  DOI：10.1104/pp.118.3.849

  日期：1998.11.1

  Abscisic acid (ABA) 8'-hydroxylase catalyzes the first step in the oxidative degradation of (+)-ABA. The development of a robust in vitro assay has now permitted detailed examination and characterization of this enzyme. Although several factors (buffer, cofactor, and source tissue) were critical in developing the assay, the most important of these was the identification of a tissue displaying high

  脱落酸（ABA）8'-羟化酶催化（+）-ABA氧化降解的第一步。强大的体外测定法的发展现已允许对该酶进行详细的检查和表征。尽管几种因素（缓冲液，辅因子和来源组织）在开发该测定方法中至关重要，但其中最重要的是鉴定显示出大量体内酶活性的组织（AJ Cutler，TM Squires，MK Loewen，JJ Balsevich [1997] J Exp Bot 48：1787-1795）。（+）-ABA 8'-羟化酶是一种完整的膜蛋白，位于悬浮培养的玉米（Zea mays）细胞的微粒体部分。（+）-ABA代谢需要NADPH和分子氧。NADH不是有效的辅助因子，尽管以限速NADPH浓度加入时，对活性（协同作用）有实质性刺激。在O2浓度小于10％（v / v）时，（+）-ABA的代谢逐渐受到抑制，在N2下非常低（小于对照的5％）。（+）-ABA 8'-羟化酶活性受到四环素（在10（-6）M时50％
• Abscisic aldehyde oxidase in leaves of Arabidopsis thaliana
  作者：Mitsunori Seo、Hanae Koiwai、Shuichi Akaba、Teruya Komano、Takayuki Oritani、Yuji Kamiya、Tomokazu Koshiba

  DOI：10.1046/j.1365-313x.2000.00812.x

  日期：2000.8

  SummaryAbscisic acid (ABA) is a plant hormone involved in seed development and responses to various environmental stresses. Oxidation of abscisic aldehyde is the last step of ABA biosynthesis and is catalysed by aldehyde oxidase (EC 1.2.3.1). We have reported the occurrence of three isoforms of aldehyde oxidase, AOα, AOβ and AOγ, in Arabidopsis thaliana seedlings, but none oxidized abscisic aldehyde. Here we report a new isoform, AOδ, found in rosette leaf extracts, which efficiently oxidizes abscisic aldehyde. AOδ was specifically recognized by antibodies raised against a recombinant peptide encoded by AAO3, one of four Arabidopsis aldehyde oxidase genes (AAO1, AAO2, AAO3 and AAO4). Functionally expressed AAO3 protein in the yeast Pichia pastoris showed a substrate preference very similar to that of rosette AOδ. These results indicate that AOδ is encoded by AAO3. AOδ produced in P. pastoris exhibited a very low Km value for abscisic aldehyde (0.51 μm), and the oxidation product was determined by gas chromatography–mass spectrometry to be ABA. Northern analysis showed that AAO3 mRNA is highly expressed in rosette leaves. When the rosette leaves were detached and exposed to dehydration, AAO3 mRNA expression increased rapidly within 3 h of the treatment. These results suggest that AOδ, the AAO3 gene product, acts as an abscisic aldehyde oxidase in Arabidopsis rosette leaves.