Video Experimental Relacionado
Updated: Jul 14, 2026
10:37
Spatial Separation of Molecular Conformers and Clusters
Published on: January 9, 2014
Reacciones iónico/moleculares de radicales catiónicos formados a partir de polipéptidos protonados a través de la
Yu Xia1, Paul A Chrisman, Sharon J Pitteri
1Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, USA.
Journal of the American Chemical Society
|September 7, 2006
Resumen
Los radicales catiónicos polipeptídicos protonados múltiples reaccionan con el oxígeno, formando adyuctos que se fragmentan al activarse. Esta reacción de oxígeno ayuda a distinguir los iones de fragmentos de péptidos para mejorar el análisis de proteínas.
Área de la Ciencia:
- Química analítica Química analítica es la que
- La bioquímica es la bioquímica.
- Química Física es la química física.
Sus antecedentes:
- Los polipéptidos protonados múltiples forman radicales cationales a través de la transferencia de electrones en la fase gaseosa.
- La disociación por transferencia de electrones (ETD) es crucial para la caracterización de la estructura primaria de los péptidos y las proteínas.
- Los radicales cationales son reactivos intermedios en las ETD.
Objetivo del estudio:
- Investigar la reacción de los radicales catiónicos polipeptídicos con el oxígeno molecular.
- Explorar la utilidad de estas reacciones para distinguir los iones de fragmentos de péptidos.
- Determinar si las reacciones iónicas / radicales pueden sondear las ubicaciones del sitio radical.
Principales métodos:
- Transferencia de electrones en la fase gaseosa a polipéptidos protonados multiplicados.
- Reacción de radicales catiónicos con oxígeno molecular en una trampa de iones electrodinámica.
- La activación por colisión de los aductos de oxígeno.
- Análisis de los productos de disociación.
Principales resultados:
- Los radicales cationales se unen fácilmente al oxígeno molecular (O2) a temperatura ambiente.
- El oxígeno añade fragmento tras la activación de colisión, perdiendo O(2), HO(*), o HO(2)(*).
- Los iones de fragmento (iones z) reaccionan con O2 , lo que los distingue de los iones c.
- Los productos de transferencia de electrones intactos también forman aductos de oxígeno con un comportamiento de disociación similar.
Conclusiones:
- Las reacciones de iones/radicales con oxígeno pueden distinguir entre los iones de fragmentos de péptidos tipo c y tipo z.
- La unión de oxígeno y la posterior disociación pueden sondear las ubicaciones del sitio radical en los productos de transferencia de electrones.
- Esta reactividad ofrece un nuevo enfoque para la identificación y caracterización de proteínas utilizando espectrometría de masas.
Videos de Conceptos Relacionados
01:19Chemical Reactions
A chemical reaction is a process by which the bonds in the atoms of substances are rearranged to generate new substances. Matter cannot be created or destroyed in a chemical reaction—the same type and number of atoms that make up the reactants are still present in the products. Merely, the rearrangement of chemical bonds produces new compounds.
Chemical Reactions Rearrange Atoms into New Substances
A chemical reaction takes starting materials—the reactants—and changes them into different...
Chemical Reactions Rearrange Atoms into New Substances
A chemical reaction takes starting materials—the reactants—and changes them into different...
03:06Reaction Mechanisms
Chemical reactions often occur in a stepwise fashion, involving two or more distinct reactions taking place in a sequence. A balanced equation indicates the reacting species and the product species, but it reveals no details about how the reaction occurs at the molecular level. The reaction mechanism (or reaction path) provides details regarding the precise, step-by-step process by which a reaction occurs.
For instance, the decomposition of ozone appears to follow a mechanism with two steps:
For instance, the decomposition of ozone appears to follow a mechanism with two steps:
02:26Chemical Reactions
A balanced chemical equation provides the information of chemical formulas of the reactants and products involved in the chemical change. A reaction’s stoichiometry helps predict how much of the reactant is needed to produce the desired amount of product, or in some cases, how much product will be formed from a specific amount of the reactant.
The relative amounts of reactants and products represented in a balanced chemical equation are often referred to as stoichiometric amounts. However, in...
The relative amounts of reactants and products represented in a balanced chemical equation are often referred to as stoichiometric amounts. However, in...
02:13Energy Diagrams, Transition States, and Intermediates
Free-energy diagrams, or reaction coordinate diagrams, are graphs showing the energy changes that occur during a chemical reaction. The reaction coordinate represented on the horizontal axis shows how far the reaction has progressed structurally. Positions along the x-axis close to the reactants have structures resembling the reactants, while positions close to the products resemble the products. Peaks on the energy diagram represent stable structures with measurable lifetimes, while other...
01:08Types of Chemical Reactions: Exchange and Reversible
An exchange reaction is a chemical reaction in which both synthesis and decomposition occur, chemical bonds are both formed and broken, and chemical energy is absorbed, stored, and released.
A special kind of exchange reaction is the oxidation-reduction reaction, or the redox reaction. These reactions involve the transfer of electrons from one compound to another. The electrons in these reactions commonly come from hydrogen atoms, which consist of an electron and a proton. A molecule gives up a...
A special kind of exchange reaction is the oxidation-reduction reaction, or the redox reaction. These reactions involve the transfer of electrons from one compound to another. The electrons in these reactions commonly come from hydrogen atoms, which consist of an electron and a proton. A molecule gives up a...
01:17Ion Exchange
Ion exchange chromatography separates charged molecules from a solution by reversibly exchanging them with mobile, or 'active', ions associated with the oppositely charged stationary phase. This method can be used to separate ions, soften and deionize water, and purify solutions. The polymers comprising the ion-exchange column are high-molecular-weight and chemically stable polymers, crosslinked to be porous and essentially insoluble. They are also functionalized with either acidic or basic...