phosphocholine

• 分子结构分类: 有机化合物 - 有机氮化合物
• 英文名称: phosphocholine
• 英文别名: 2-(Trimethylazaniumyl)ethyl phosphate
• 化学式: C₅H₁₃NO₄P
• 分子量: 182.136
• InChiKey: YHHSONZFOIEMCP-UHFFFAOYSA-M

计算性质

• 辛醇/水分配系数(LogP)：
  -1.7
• 重原子数：
  11
• 可旋转键数：
  3
• 环数：
  0.0
• sp3杂化的碳原子比例：
  1.0
• 拓扑面积：
  72.4
• 氢给体数：
  0
• 氢受体数：
  4

反应信息

• 作为反应物：
  描述：

  phosphocholine 在 alkaline phosphatase 作用下， 生成 胆碱
  参考文献：
  名称：

  使用 PUB 模块对 (Pyro-)Phosphate 进行紫外光谱检测

  摘要：

  尽管正磷酸盐和焦磷酸盐在生物化学中普遍存在，但缺乏操作简单且通用的高通量方法来量化它们。我们在此介绍了 PUB，这是一个通过连续紫外光谱监测 5- b romouridine磷酸解来检测磷酸盐的模块。PUB 模块使用廉价、稳定的试剂，可用于生化测定中的连续和不连续反应监测，以检测跨越近 4 个数量级的（焦）磷酸盐浓度，如代表性用例所示。

  DOI：

  10.1021/acs.analchem.1c05356
• 作为产物：
  描述：

  Γ-O-十八烷基-L-Α-溶血卵磷脂 、 水 生成 batyl alcohol 、 氢(+1)阳离子 、 phosphocholine
  参考文献：
  名称：

  Function of the Cloned Putative Neutral Sphingomyelinase as Lyso-platelet Activating Factor-Phospholipase C

  摘要：

  Sphingolipids such as ceramide and sphingosine have been regarded as novel signal mediators in cells. However, the mechanisms of generation of these lipids upon various stimulation remain to be elucidated. Neutral sphingomyelinase (N-SMase) is one of the key enzymes in the generation of ceramide, and recently the cloning of a putative N-SMase was reported. Because the function of the protein was unclear in the previous report, we investigated the role it plays in cells. N-SMase activity in cells overexpressing the protein with hexa-histidine tag was immunoprecipitated with anti-hexa histidine antibody. The metabolism of ceramide and SM was not apparently affected in overexpressing cells. Radiolabeling experiments using [H-3]palmitic acid or [H-3] hexadecanol demonstrated an accumulation of 1-O-alkyl-sn-glycerol and a corresponding decrease of 1-alkyl-2-acyl-sn-glycero-3-phosphocholine in overexpressing cells. In vitro studies showed that both 1-acyl-2-lyso-sn-glycero-3-phosphocholine (lyso-PC) and 1-O-alkyl-2-lyso-sn-glycero-3-phosphocholine (lyso-platelet activating factor (lyso-PAF)) are good substrates of the protein. In further radiolabeling experiments, 1-acyl-lyso-PC was predominantly and equally metabolized into diacyl-PC in both vector and overexpressing cells. On the other hand, 1-O-alkyl-lyso-PC (lyso-PAF) was metabolized into both diradyl-PC and 1-O-alkyl-glycerol in overexpressing cells but only into diradyl-PC in vector cells. These results suggest that the protein acts as lyso-PAF-PLC rather than lyso-PC-PLC or N-SMase in cells.

  DOI：

  10.1074/jbc.274.53.38131

文献信息

• Crystal Structure of a Mammalian CTP: Phosphocholine Cytidylyltransferase Catalytic Domain Reveals Novel Active Site Residues within a Highly Conserved Nucleotidyltransferase Fold
  作者：Jaeyong Lee、Joanne Johnson、Ziwei Ding、Mark Paetzel、Rosemary B. Cornell

  DOI：10.1074/jbc.m109.053363

  日期：2009.11

  CTP:phosphocholine cytidylyltransferase (CCT) is the key regulatory enzyme in the synthesis of phosphatidylcholine, the most abundant phospholipid in eukaryotic cell membranes. The CCT-catalyzed transfer of a cytidylyl group from CTP to phosphocholine to form CDP-choline is regulated by a membrane lipid-dependent mechanism imparted by its C-terminal membrane binding domain. We present the first analysis

  CTP：磷酸胆碱胞苷转移酶 (CCT) 是合成磷脂酰胆碱的关键调控酶，磷脂酰胆碱是真核细胞膜中含量最丰富的磷脂。CCT 催化的胞苷酰基团从 CTP 转移到磷酸胆碱以形成 CDP 胆碱是由其 C 端膜结合域赋予的膜脂依赖性机制调节的。我们首次分析了真核 CCT 的晶体结构。跨越残基 1-236 (CCT236) 的大鼠 CCTalpha 的删除构造缺乏调节域，因此显示组成性活动。2.2-A 结构揭示了与反应产物 CDP-胆碱复合的 CCT236 同源二聚体。每条链由一个完整的催化结构域组成，具有密切相关的 N 端延伸，它与催化域一起形成二聚体界面。尽管 CCT236 结构揭示了与胞苷酸转移酶超家族的其他成员保守的结合胞苷的元素，但它也具有非保守的活性位点残基 His-168 和 Tyr-173，它们与 CDP-胆碱的 β-磷酸发生关键相互作用. 诱变和动力学分析证实了它们在磷酸胆碱结合和催化
• Molecular cloning and characterization of the gene encoding cholinephosphate cytidylyltransferase in Saccharomyces cerevisiae
  作者：Yuko TSUKAGOSHI、Jun-ichi NIKAWA、Satoshi YAMASHITA

  DOI：10.1111/j.1432-1033.1987.tb13635.x

  日期：1987.12

  The structural gene for cholinephosphate cytidylyltransferase (CCT) was isolated from a Saccharomyces cerevisiae genomic library by means of complementation in a mutant of the yeast defective in the enzyme. The cloned DNA restored both the growth and cholinephosphate cytidylyltransferase activity of the mutant. Whereas the enzyme of the mutant was thermolabile, the enzyme produced by the transformant was indistinguishable in heat stability from that produced by the wild type. Strains carrying a multicopy recombinant plasmid overproduced cholinephosphate cytidylyltransferase. The overproduction of the enzyme brought about an increase in the synthesis of CDPcholine in the transformant, but there was no increase in the overall rate of phosphatidylcholine synthesis. The cloned DNA was subcloned into a 2.5‐kb DNA fragment. The nucleotide sequence which contained CCT was determined by the dideoxy chain‐termination method. The sequence contained an open reading frame capable of encoding a protein of 424 amino acid residues with a calculated relative molecular mass of 49379.31. Northern blot analysis showed that this DNA segment is transcribed in yeast cells and the length of the transcript is consistent with the putative translation product. Hydropathy analysis according to Kyte and Doolittle indicated that the primary translation product contains extended hydrophilic stretches in its N‐ and C‐terminal regions. The primary translation product contains a region showing local sequence homology with nucleotidyl‐transfer enzymes such as DNA polymerase (Escherichia coli), CDPdiacylglycerol pyrophosphatase (E. coli), 3‐deoxy‐manno‐octulosonate cytidylyltransferase (E. coli) and DNA ligase (T4 phage), suggesting that these five enzymes are evolutionarily related. Statistically significant sequence homology was also noted between the human c‐fos gene product and the enzyme.

  通过互补法，从酿酒酵母（Saccharomyces cerevisiae）的基因组文库中分离出了胆碱磷酸胞苷转移酶（CCT）的结构基因。克隆的DNA恢复了突变体的生长和胆碱磷酸胞苷转移酶活性。突变体的酶热不稳定性，而转化体产生的酶在热稳定性上与野生型产生的酶无法区分。携带多拷贝重组质粒的菌株过量产生了胆碱磷酸胞苷转移酶。该酶的过量产生使转化体中CDP胆碱的合成增加，但整体磷脂酰胆碱的合成速率并未增加。克隆的DNA被亚克隆到一个2.5-kb的DNA片段中。包含CCT的核苷酸序列通过巢式链终止法确定。该序列包含一个开放阅读框，可编码一个由424个氨基酸残基组成的蛋白质，其计算出的相对分子质量为49379.31。Northern印迹分析显示，该DNA片段在酵母细胞中转录，且转录本的长度与推测的翻译产物一致。根据Kyte和Doolittle的疏水性分析，主要翻译产物在N端和C端区域具有扩展的疏水区域。主要翻译产物中有一个区域显示出与脱氧核核苷酸转移酶（如<;大肠杆菌;DNA聚合酶、CDP二酰基甘油焦磷酸水解酶、3-去氧-;曼诺;辛酮酸胞苷转移酶以及T4噬菌体DNA连接酶）的局部序列同源性，表明这五种酶在进化上相关。此外，人;c-fos;基因产物与该酶之间也存在统计学意义上的序列同源性。
• Differential Role of Human Choline Kinase α and β Enzymes in Lipid Metabolism: Implications in Cancer Onset and Treatment
  作者：David Gallego-Ortega、Ana Ramirez de Molina、Maria Angeles Ramos、Fatima Valdes-Mora、Maria Gonzalez Barderas、Jacinto Sarmentero-Estrada、Juan Carlos Lacal

  DOI：10.1371/journal.pone.0007819

  日期：——

  Background The Kennedy pathway generates phosphocoline and phosphoethanolamine through its two branches. Choline Kinase (ChoK) is the first enzyme of the Kennedy branch of synthesis of phosphocholine, the major component of the plasma membrane. ChoK family of proteins is composed by ChoKα and ChoKβ isoforms, the first one with two different variants of splicing. Recently ChoKα has been implicated in the carcinogenic process, since it is over-expressed in a variety of human cancers. However, no evidence for a role of ChoKβ in carcinogenesis has been reported. Methodology/Principal Findings Here we compare the in vitro and in vivo properties of ChoKα1 and ChoKβ in lipid metabolism, and their potential role in carcinogenesis. Both ChoKα1 and ChoKβ showed choline and ethanolamine kinase activities when assayed in cell extracts, though with different affinity for their substrates. However, they behave differentially when overexpressed in whole cells. Whereas ChoKβ display an ethanolamine kinase role, ChoKα1 present a dual choline/ethanolamine kinase role, suggesting the involvement of each ChoK isoform in distinct biochemical pathways under in vivo conditions. In addition, while overexpression of ChoKα1 is oncogenic when overexpressed in HEK293T or MDCK cells, ChoKβ overexpression is not sufficient to induce in vitro cell transformation nor in vivo tumor growth. Furthermore, a significant upregulation of ChoKα1 mRNA levels in a panel of breast and lung cancer cell lines was found, but no changes in ChoKβ mRNA levels were observed. Finally, MN58b, a previously described potent inhibitor of ChoK with in vivo antitumoral activity, shows more than 20-fold higher efficiency towards ChoKα1 than ChoKβ. Conclusion/Significance This study represents the first evidence of the distinct metabolic role of ChoKα and ChoKβ isoforms, suggesting different physiological roles and implications in human carcinogenesis. These findings constitute a step forward in the design of an antitumoral strategy based on ChoK inhibition.

  背景 肯尼迪途径通过其两个分支产生磷脂酰胆碱和磷脂酰乙醇胺。胆碱激酶（ChoK）是肯尼迪途径合成磷脂酰胆碱的第一种酶，磷脂酰胆碱是血浆膜的主要成分。胆碱激酶家族由ChoKα和ChoKβ同工型组成，前者有2种不同的剪接变体。最近，ChoKα被证实与致癌过程有关，因为它会在多种人类癌症中过度表达。然而，目前尚无证据表明ChoKβ在致癌过程中发挥作用。 方法/主要发现 在此，我们比较了ChoKα1和ChoKβ在脂质代谢中的体外和体内特性，以及它们在致癌过程中的潜在作用。在细胞提取物中检测时，ChoKα1和ChoKβ均表现出胆碱和乙醇胺激酶活性，尽管它们对底物的亲和力不同。然而，当它们在整细胞中过度表达时，它们的行为会有所不同。ChoKβ表现出乙醇胺激酶的作用，而ChoKα1则表现出胆碱/乙醇胺双激酶的作用，这表明在体内条件下，每种ChoK同工型都参与不同的生化途径。此外，当在HEK293T或MDCK细胞中过度表达ChoKα1时，它会产生致癌作用，而ChoKβ的过度表达则不足以诱导体外细胞转化或体内肿瘤生长
• Comparative modelling of human PHOSPHO1 reveals a new group of phosphatases within the haloacid dehalogenase superfamily
  作者：A. J. Stewart、R. Schmid、C. A. Blindauer、S. J. Paisey、C. Farquharson

  DOI：10.1093/protein/gzg126

  日期：2003.12.1

  PHOSPHO1 is a recently identified phosphatase whose expression is upregulated in mineralizing cells and is implicated in the generation of inorganic phosphate for matrix mineralization, a process central to skeletal development. The enzyme is a member of the haloacid dehalogenase (HAD) superfamily of magnesium‐dependent hydrolases. However, the natural substrate(s) is as yet unidentified and to date no structural information is known. We have identified homologous proteins in a number of species and have modelled human PHOSPHO1 based upon the crystal structure of phosphoserine phosphatase (PSP) from Methanococcus jannaschii. The model includes the catalytic Mg2+ atom bound via three conserved Asp residues (Asp32, Asp34 and Asp203); O‐ligands are also provided by a phosphate anion and two water molecules. Additional residues involved in PSP‐catalysed hydrolysis are conserved and are located nearby, suggesting both enzymes share a similar reaction mechanism. In PHOSPHO1, none of the PSP residues that confer the enzyme’s substrate specificity (Arg56, Glu20, Met43 and Phe49) are conserved. Instead, we propose that two fully conserved Asp residues (Asp43 and Asp123), not present in PSPs contribute to substrate specificity in PHOSPHO1. Our findings show that PHOSPHO1 is not a member of the subfamily of PSPs but belongs to a novel, closely related enzyme group within the HAD superfamily.

  PHOSPHO1 是最近发现的一种磷酸酶，其表达在矿化细胞中上调，与基质矿化过程中无机磷酸盐的生成有关，这是骨骼发育的一个核心过程。该酶是依赖镁的水解酶卤酸脱卤酶（HAD）超家族的成员。然而，该酶的天然底物尚未确定，结构信息也尚不清楚。我们已经确定了一些物种中的同源蛋白，并根据梅氏球菌（Methanococcus jannaschii）磷酸丝氨酸磷酸酶（PSP）的晶体结构建立了人类 PHOSPHO1 的模型。该模型包括通过三个保守的 Asp 残基（Asp32、Asp34 和 Asp203）结合的催化 Mg2+ 原子；磷酸阴离子和两个水分子也提供了 O 配体。参与 PSP 催化水解的其他残基也是保守的，而且位于附近，这表明这两种酶具有相似的反应机制。在 PHOSPHO1 中，赋予该酶底物特异性的 PSP 残基（Arg56、Glu20、Met43 和 Phe49）都没有保守。相反，我们认为两个完全保守的 Asp 残基（Asp43 和 Asp123）不存在于 PSP 中，它们有助于 PHOSPHO1 的底物特异性。我们的研究结果表明，PHOSPHO1 不是 PSPs 亚家族的成员，而是属于 HAD 超家族中一个新的、密切相关的酶组。
• Human PHOSPHO1 exhibits high specific phosphoethanolamine and phosphocholine phosphatase activities
  作者：Scott J. ROBERTS、Alan J. STEWART、Peter J. SADLER、Colin FARQUHARSON

  DOI：10.1042/bj20040511

  日期：2004.8.15

  Human PHOSPHO1 is a phosphatase enzyme for which expression is upregulated in mineralizing cells. This enzyme has been implicated in the generation of Pi for matrix mineralization, a process central to skeletal development. PHOSPHO1 is a member of the haloacid dehalogenase (HAD) superfamily of Mg2+-dependent hydrolases. However, substrates for PHOSPHO1 are, as yet, unidentified and little is known about its activity. We show here that PHOSPHO1 exhibits high specific activities toward phosphoethanolamine (PEA) and phosphocholine (PCho). Optimal enzymic activity was observed at approx. pH 6.7. The enzyme shows a high specific Mg2+-dependence, with apparent Km values of 3.0 μM for PEA and 11.4 μM for PCho. These results provide a novel mechanism for the generation of Pi in mineralizing cells from PEA and PCho.

  人类 PHOSPHO1 是一种在矿化细胞中表达上调的磷酸酶。这种酶与基质矿化所需的π的生成有关，而基质矿化是骨骼发育的核心过程。PHOSPHO1 是 Mg2+ 依赖性水解酶卤酸脱卤酶（HAD）超家族的成员。然而，PHOSPHO1 的底物尚未确定，对其活性也知之甚少。我们在这里发现，PHOSPHO1 对磷酸乙醇胺（PEA）和磷酸胆碱（PCho）具有很高的特异性活性。在 pH 值约为 6.7 时观察到了最佳的酶活性。该酶显示出高度的特异性 Mg2+ 依赖性，对 PEA 的表观 Km 值为 3.0 μM，对 PCho 的表观 Km 值为 11.4 μM。这些结果为矿化细胞中 PEA 和 PCho 产生 Pi 提供了一种新的机制。

表征谱图