镁离子(Mg2+) | 22537-22-0

• 分子结构分类: 无机化合物 - 均相金属化合物 - 均相碱土金属化合物
• 中文名称: 镁离子(Mg2+)
• 英文名称: Magnesium Cation
• 英文别名: magnesium(2+)
• CAS: 22537-22-0
• 化学式: Mg+2
• 分子量: 24.305
• InChiKey: JLVVSXFLKOJNIY-UHFFFAOYSA-N

物化性质

• 密度：
  1.06 g/mL at 20 °C
• 溶解度：
  可溶于水中
• 物理描述：
  Solid
• 沸点：
  1100 °C
• 熔点：
  651 °C

计算性质

• 辛醇/水分配系数(LogP)：
  -0.38
• 重原子数：
  1
• 可旋转键数：
  0
• 环数：
  0.0
• sp3杂化的碳原子比例：
  0.0
• 拓扑面积：
  0
• 氢给体数：
  0
• 氢受体数：
  0

安全信息

• 危险等级：
  8
• 危险品标志：
  Xi
• 安全说明：
  S26
• 危险类别码：
  R8
• 包装等级：
  III

反应信息

• 作为反应物：
  描述：

  adenosine 5'-triphosphate 、 水 、 镁离子(Mg2+) 、 protoporphyrin IX 生成 adenosine 5'-diphosphate 、 氢(+1)阳离子 、 Mg-protoporphyrin IX 、 H3PO4
  参考文献：
  名称：

  AAA模块和整合素I域之间的相互作用可能调节镁螯合酶的功能。

  摘要：

  在叶绿素的生物合成中，Mg（2+）插入原卟啉IX是由三亚基（BchI，BchD和BchH）酶镁螯合酶在ATP依赖性反应中催化的。在这项工作中，我们介绍了ATP结合亚基BchI的三维结构。该结构已通过多波长异常色散法解决，并以2.1 A的分辨率精炼至22.2％的晶体学R因子（R（游离）= 24.5％）。它属于伴侣分子样的“与多种细胞活性有关的ATPase”（AAA）ATPase家族，具有新颖的结构域排列：C末端螺旋结构域位于核苷酸结合位点后面，而在其他已知的AAA模块结构位于顶部。在ATP存在下通过电子显微镜检查BchI溶液表明，BchI，与其他AAA蛋白一样，形成寡聚环结构。对BchD亚基氨基酸序列的分析表明，该序列N端有一个AAA模块，C端有一个整合素I结构域。建议将连接这两个结构域的酸性富含脯氨酸的区域通过与BchI核苷酸结合结构域表面带正电荷的裂隙结合，从而促进BchI和BchD的缔

  DOI：

  10.1006/jmbi.2001.4834
• 作为产物：
  描述：

  chlorophyll a 、 氢(+1)阳离子 生成 镁离子(Mg2+) 、 pheophytin a
  参考文献：
  名称：

  Removal of Magnesium by Mg-dechelatase Is a Major Step in the Chlorophyll-Degrading Pathway in Ginkgo biloba in the Process of Autumnal Tints

  摘要：

  秋色是最明显和迷人的自然现象之一，但落叶树叶绿素（Chl）降解机制尚未完全阐明。在这项研究中，我们分析了银杏叶在秋季变色过程中不同阶段的Chl相关化合物组成，并确定了初始Chl降解酶的活性。HPLC分析仅检测到苯基叶绿素a（Pheo a，无镁的Chl a）在黄叶中存在，并且黄叶中Mg脱螯酶的活性高于绿叶。这些发现表明，银杏中Chl a的镁离子去除比脱叶基化先发生。

  DOI：

  10.1515/znc-2000-11-1213

文献信息

• Mechanism and regulation of Mg-chelatase
  作者：J. Caroline WALKER、D. Robert WILLOWS

  DOI：10.1042/bj3270321

  日期：1997.10.15

  Mg-chelatase catalyses the insertion of Mg into protoporphyrin IX (Proto). This seemingly simple reaction also is potentially one of the most interesting and crucial steps in the (bacterio)chlorophyll (Bchl/Chl)-synthesis pathway, owing to its position at the branch-point between haem and Bchl/Chl synthesis. Up until the level of Proto, haem and Bchl/Chl synthesis share a common pathway. However, at the point of metal-ion insertion there are two choices: Mg2+ insertion to make Bchl/Chl (catalysed by Mg-chelatase) or Fe2+ insertion to make haem (catalysed by ferrochelatase). Thus the relative activities of Mg-chelatase and ferrochelatase must be regulated with respect to the organism's requirements for these end products . How is this regulation achieved? For Mg-chelatase, the recent design of an in vitro assay combined with the identification of Bchl-biosynthetic enzyme genes has now made it possible to address this question. In all photosynthetic organisms studied to date, Mg-chelatase is a three-component enzyme, and in several species these proteins have been cloned and expressed in an active form. The reaction takes place in two steps, with an ATP-dependent activation followed by an ATP-dependent chelation step. The activation step may be the key to regulation, although variations in subunit levels during diurnal growth may also play a role in determining the flux through the Bchl/Chl and haem branches of the pathway.

  Mg-螯合酶催化将镁插入原卟啉IX（Proto）中。这个看似简单的反应也是（细菌）叶绿素（Bchl / Chl）合成途径中最有趣和关键的步骤之一，因为它位于血红素和Bchl / Chl合成的分支点上。在Proto的水平上，血红素和Bchl / Chl的合成有一个共同的途径。然而，在金属离子插入的时候，有两个选择：Mg2 +插入以制造Bchl / Chl（由Mg-螯合酶催化）或Fe2 +插入以制造血红素（由铁螯合酶催化）。因此，相对于生物对这些终产物的要求，Mg-螯合酶和铁螯合酶的相对活性必须得到调节。这种调节是如何实现的？对于Mg-螯合酶，最近设计了一种体外测定结合Bchl生物合成酶基因的方法，现在可以解决这个问题。到目前为止，所有研究的光合生物中，Mg-螯合酶都是一个三组分酶，在几种物种中，这些蛋白质已被克隆并以活性形式表达。该反应分两步进行，先是ATP依赖的激活步骤，然后是ATP依赖的螯合步骤。激活步骤可能是调节的关键，尽管在昼夜生长期间亚单位水平的变化也可能在确定通路中Bchl / Chl和血红素分支方面发挥作用。
• Removal of Magnesium by Mg-dechelatase Is a Major Step in the Chlorophyll-Degrading Pathway in Ginkgo biloba in the Process of Autumnal Tints
  作者：Lei Tang、Atsushi Okazawa、Eiichiro Fukusaki、Akio Kobayashi

  DOI：10.1515/znc-2000-11-1213

  日期：2000.12.1

  Autumnal tints are one of the most manifest and fascinating natural phenomena, but the mechanism of chlorophyll (Chl)-breakdown in deciduous trees has not been fully elucidated. In this study, we analyzed the composition of Chl-related compounds and determined the activities of initial Chl-degrading enzymes in Ginkgo leaves at various stages in the process of autumnal coloring. Only pheophytin a (Pheo a, Mg-free Chl a) was detected in yellow leaves by HPLC analysis, and the activity of Mg-dechelatase in yellow leaves was found to be higher than in green leaves. These findings showed that the removal of magnesium from Chl a occurred in advance of dephytylation in the Ginkgo.

  秋色是最明显和迷人的自然现象之一，但落叶树叶绿素（Chl）降解机制尚未完全阐明。在这项研究中，我们分析了银杏叶在秋季变色过程中不同阶段的Chl相关化合物组成，并确定了初始Chl降解酶的活性。HPLC分析仅检测到苯基叶绿素a（Pheo a，无镁的Chl a）在黄叶中存在，并且黄叶中Mg脱螯酶的活性高于绿叶。这些发现表明，银杏中Chl a的镁离子去除比脱叶基化先发生。
• Enzymatic Chlorophyll Degradation in Wheat Near-Isogenic Lines Elicited by Cereal Aphid (Homoptera: Aphididae) Feeding
  作者：Tao Wang、Sharron S. Quisenberry、Xinzhi Ni、Vicki Tolmay

  DOI：10.1603/0022-0493-97.2.661

  日期：2004.4.1

  Chlorophyll degradation enzyme (i.e., chlorophyllase, Mg-dechelatase, and chlorophyll oxidase) activities of aphid-infested and uninfested 'Tugela' and Tugela near-isogenic wheat lines (i.e., Tugela-Dn1, Tugela-Dn2, and Tugela-Dn5) were assayed. Chlorophyllase activity was higher in bird cherry-oat aphid, Rhopalosiphum padi (L.) (Homoptera: Aphididae), -infested wheat lines compared with Russian wheat aphid, Diuraphis noxia (Mordvilko) (Homoptera: Aphididae)]-infested and uninfested plants. Mg-dechelatase activity was higher in D. noxia-infested wheat lines than in R. padi-infested and uninfested plants. Also, Mg-dechelatase activity was lower in Tugela wheat infested with D. noxia than in Tugela near-isogenic lines with Dn genes. Based on the in vitro assays of chlorophyll degradation enzyme (i.e., chlorophyllase and Mg-dechelatase) activities, we proposed that the chlorotic symptoms observed on D. noxia-infested Tugela wheat were most likely to be elicited by unbalanced chlorophyll biosynthesis and degradation.
• Mg-dechelation activity in radish cotyledons with artificial and native substrates, Mg-chlorophyllin a and chlorophyllide a
  作者：Toshiyuki Suzuki、Tadashi Kunieda、Fumiko Murai、Satoshi Morioka、Yuzo Shioi

  DOI：10.1016/j.plaphy.2005.03.009

  日期：2005.5

  The Mg-dechelation activity in extracts from radish (Raphanus sativus L.) cotyledons was investigated using an artificial substrate, Mg-chlorophyllin a (Chlin) and the native substrate, chlorophyllide a (Chlide). In addition to a known a small molecular weight metal-chelating substance (MCS), Mg-releasing protein (MRP) was present when Chlin was used as the substrate. However, only MCS had Mg-dechelation activity with the native substrate. To examine the possibility of the dissociation of MRP into a protein moiety and a small molecular mass compound with an activity like MCS, extraction with low and high ionic strength buffers was carried out. No evidence was obtained that MCS is a moiety of MRP, however. Inhibitor studies showed that MCS and MRP had different susceptibilities to the inhibitors, especially to the chelators tiron and EDTA when Chlin was used as the substrate. Tiron had no effect on MRP, but it severely reduced MCS activity in both substrates. The activity of MRP increased during senescence, indicating the induction of MRP, while the activity of MCS was almost unchanged. These results suggest different reaction mechanisms by independent compounds. These findings suggest that MRP and MCS are present independently, and MCS is postulated to be a substance that catalyzes the Mg-dechelation reaction in the breakdown pathway of Ch1, although MCS was not induced during senescence. The properties of MRP and MCS in relation to the small molecular mass substance obtained from strawberry fruit are also discussed. (c) 2005 Elsevier SAS. All rights reserved.
• Interplay between an AAA module and an integrin I domain may regulate the function of magnesium chelatase
  作者：M.N Fodje、A Hansson、M Hansson、J.G Olsen、S Gough、R.D Willows、S Al-Karadaghi

  DOI：10.1006/jmbi.2001.4834

  日期：2001.8

  These are proposed to bind the integrin I domain of BchD during the functional cycle of magnesium chelatase, linking porphyrin metallation by BchH to ATP hydrolysis by BchI. An integrin I domain and an acidic and proline-rich region have been identified in subunit CobT of cobalt chelatase, clearly demonstrating its homology to BchD. These findings, for the first time, provide an insight into the subunit

  在叶绿素的生物合成中，Mg（2+）插入原卟啉IX是由三亚基（BchI，BchD和BchH）酶镁螯合酶在ATP依赖性反应中催化的。在这项工作中，我们介绍了ATP结合亚基BchI的三维结构。该结构已通过多波长异常色散法解决，并以2.1 A的分辨率精炼至22.2％的晶体学R因子（R（游离）= 24.5％）。它属于伴侣分子样的“与多种细胞活性有关的ATPase”（AAA）ATPase家族，具有新颖的结构域排列：C末端螺旋结构域位于核苷酸结合位点后面，而在其他已知的AAA模块结构位于顶部。在ATP存在下通过电子显微镜检查BchI溶液表明，BchI，与其他AAA蛋白一样，形成寡聚环结构。对BchD亚基氨基酸序列的分析表明，该序列N端有一个AAA模块，C端有一个整合素I结构域。建议将连接这两个结构域的酸性富含脯氨酸的区域通过与BchI核苷酸结合结构域表面带正电荷的裂隙结合，从而促进BchI和BchD的缔