性化酸胆的电子转移解离允许容易的双键和sn-1/sn-2定位
John Carlos1,2, Clarisse Gosset-Erard1, Jean-Yves Salpin2
1Université Paris-Saclay, CNRS, ICSN, UPR 2301, Gif-sur-Yvette, France.
Rapid communications in mass spectrometry : RCM
|December 2, 2024
概括
使用质谱学 (MS) 的电子转移解离 (ETD) 可使酸丁胆 (PC) 的异构水平表征成为可能. 这种方法精确地确定双键和立体特定编号 (sn) 位置,无需复杂的样本准备或仪器更改.
科学领域:
- 分析化学 分析化学
- 生物化学 生化学
- 质谱测量质量谱测量
背景情况:
- 脂质异构体是新兴的生物标志物,需要先进的表征方法.
- 很少有商业方法可以在不衍生的情况下对异构水平的酸丁胆 (PC) 进行分析.
- 电子转移解离 (ETD) 被用于PC异构体的表征.
研究的目的:
- 开发和验证ETD-MS方法来确定PC物种中的双键和立体特异编号 (sn) 位置.
- 为了使PCs在不需要复杂的样本准备或仪器修改的情况下能够在异构水平上进行注释.
主要方法:
- 使用盐形成[PC + 2Alk]2+的双重电荷PC的分析.
- 使用ETD-MS2进行sn-position注释,使用ETD-CID-MS3进行双键定位.
- 来自密度函数理论 (DFT) 计算和循环离子运动谱学 (c-IMS-MS/MS) 的支持.
主要成果:
- ETD-MS2显示了系统的sn-2裂变,通过激素离子驱动机制实现了sn定位.
- 这与CID形成鲜明对比,其中酸盐的位置影响了键裂变.
- ETD-CID-MS成功地将单不和和多不和PC异构体中的双键局部化.
结论:
- 已建立的ETD-MS2和ETD-CID-MS3解离规则允许PC的异构层次注释.
- 该方法不需要仪器修改或复杂的样本准备.
- 有可能与液态色谱 (LC) 分离进行合,用于复杂混合物分析.
相关概念视频
Synthesis of Phosphatidylcholine in the ER Membrane
3.0K
The ER synthesizes lipids for building cell membranes and performing cellular functions such as energy storage and signaling. The lipid synthesis machinery embedded in the ER membrane primarily collects all reactants from the cytosol. Following synthesis, the secretory pathway and the ER contact sites distribute these lipids to other cellular organelles. Additionally, the energy-rich triacylglycerides are transported from the ER via lipid droplets.
The major components of all eukaryotic cell...
The major components of all eukaryotic cell...
3.0K
Introduction to Electrophilic Addition Reactions of Alkenes
7.7K
The double bond in a simple, unconjugated alkene is a region of high electron density that can act as a weak base or a nucleophile. The filled π orbital (HOMO) of the double bond can interact with the empty LUMO of an electrophile. A bonding interaction occurs when the electrophile attacks between the two carbons; the electrophile then accepts a pair of electrons from the π bond and undergoes addition across the double bond, yielding a single product.
Addition and elimination...
Addition and elimination...
7.7K
Asymmetric Lipid Bilayer
7.2K
Biological membranes show uneven distribution of different types of lipids in the inner and outer layers, resulting in transverse asymmetric membranes. The treatment of the erythrocyte membrane with the enzyme phospholipase confirmed the asymmetric nature of the lipid bilayer. The enzyme hydrolyzes lipids into fatty acids and hydrophilic groups. The phospholipase acts only on the outer layer of the membrane, while the inner layer remains intact. The phospholipase treatment resulted in 80%...
7.2K
α-Alkylation of Ketones via Enolate Ions
3.0K
Ketones with α protons are deprotonated by strong bases like lithium diisopropylamide (LDA) to form enolate ions. The anion is stabilized by resonance, and its hybrid structure exhibits negative charges on the carbonyl oxygen and the α carbon. This ambident nucleophile can attack an electrophile via two possible sites: the carbonyl oxygen, known as O-attack, or the α carbon, known as C-attack. The nucleophilic attack via the carbanionic site is preferred. This is due to the...
3.0K
SN2 Reaction: Transition State
9.5K
An SN2 reaction of an alkyl halide is a single-step process in which bond formation between the nucleophile and the substrate and bond breaking between the substrate and the halide occurs simultaneously through a transition state without forming an intermediate.
When the nucleophile approaches the electrophilic carbon with its lone pairs, the halide acts as a leaving group and moves away with the electron-pair bonded to the carbon. Dotted partial bonds represent the bonds being formed or broken...
When the nucleophile approaches the electrophilic carbon with its lone pairs, the halide acts as a leaving group and moves away with the electron-pair bonded to the carbon. Dotted partial bonds represent the bonds being formed or broken...
9.5K
SN1 Reaction: Stereochemistry
8.3K
This lesson provides an in-depth discussion of the stereochemical outcomes in an SN1 reaction.
In the first step of an SN1 reaction, the bond between the electrophilic carbon and the leaving group ionizes to generate the carbocation intermediate. The second step of the mechanism is the nucleophilic attack.
In the formed carbocation, the positively charged carbon is sp2 hybridized with a trigonal planar geometry. As all the three substituents lie on the same plane, a plane of symmetry for the...
In the first step of an SN1 reaction, the bond between the electrophilic carbon and the leaving group ionizes to generate the carbocation intermediate. The second step of the mechanism is the nucleophilic attack.
In the formed carbocation, the positively charged carbon is sp2 hybridized with a trigonal planar geometry. As all the three substituents lie on the same plane, a plane of symmetry for the...
8.3K


