Video Experimental Relacionado
Updated: Jul 9, 2026
08:31
Anaerobic Protein Purification and Kinetic Analysis via Oxygen Electrode for Studying DesB Dioxygenase Activity and Inhibition
Published on: October 3, 2018
Los nitróxidos eliminan los radicales tiilo catalizados por la mieloperoxidasa en los sistemas modelo y en las
Grigory G Borisenko1, Ian Martin, Qing Zhao
1Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA. grigoryb@yahoo.com
Journal of the American Chemical Society
|July 30, 2004
Resumen
Los radicales de nitróxido reaccionan con los radicales glutationiles dañinos (GS) para formar aminas secundarias, una vía previamente desconocida. Esta interacción protege las células mediante la preservación del glutatión (GSH) y la eliminación de los radicales libres.
Área de la Ciencia:
- La bioquímica es la bioquímica.
- Química de los radicales libres.
- Biología celular Biología celular.
Sus antecedentes:
- Los radicales de nitróxido son antioxidantes conocidos que eliminan los radicales reactivos en los sistemas biológicos.
- El glutatión (GSH) es el principal antioxidante intracelular, pero su forma radical (GS(*)) puede ser perjudicial.
- Las interacciones entre los nitróxidos, GS(*), y los tiolos, así como el metabolismo de los nitróxidos en las células, no se comprenden bien.
Objetivo del estudio:
- Investigar la interacción entre los radicales de nitróxido y los radicales de glutationilo (GS(*)).
- Para dilucidar las vías metabólicas de los nitróxidos dentro de las células, en particular su conversión en aminas secundarias.
- Para caracterizar los mecanismos antioxidantes de los nitróxidos en las células vivas.
Principales métodos:
- Desarrolló un método sensible utilizando Ac-Tempo (un conjugado fluorescente de acridina-nitróxido) para detectar GS.
- Utilizó la espectroscopia de resonancia paramagnética de electrones (EPR) para monitorear la desintegración de la señal de nitróxido.
- Empleó cromatografía líquida de alto rendimiento (HPLC) y espectrometría de masas para identificar productos de reacción.
- Reacciones estudiadas en células HL-60 estimuladas con H(2) O(2) y fenol.
Principales resultados:
- GS(*) los radicales reaccionan de manera eficiente e irreversible con los nitróxidos para formar aminas secundarias.
- La señal EPR de Ac-Tempo disminuyó, y la fluorescencia de la acridina aumentó tras la reacción con GS.
- El análisis HPLC-MS mostró Ac-Tempo convertido en acridina-piperidina y GSH oxidado a ácido sulfónico.
- Las células protegidas por Ac-Tempo de la toxicidad del fenol/GS(*) y la GSH intracelular preservada.
Conclusiones:
- Los nitróxidos reaccionan con GS para formar aminas secundarias, lo que representa una nueva vía metabólica.
- Ac-Tempo sirve como una sonda eficaz para la detección de GS(*) y la caracterización de las interacciones nitróxido-GS(*).
- Los nitróxidos exhiben actividad antioxidante a través de un nuevo mecanismo que involucra la eliminación y preservación de GSH.
Videos de Conceptos Relacionados
01:28Electron Transport Chains
The final stage of cellular respiration is oxidative phosphorylation that consists of two steps: the electron transport chain and chemiosmosis. The electron transport chain is a set of proteins found in the inner mitochondrial membrane in eukaryotic cells. Its primary function is to establish a proton gradient that can be used during chemiosmosis to produce ATP and generate electron carriers, such as NAD+ and FAD, that are used in glycolysis and the citric acid cycle.
The ETC is comprised of...
The ETC is comprised of...
02:50Catalysis
The presence of a catalyst affects the rate of a chemical reaction. A catalyst is a substance that can increase the reaction rate without being consumed during the process. A basic comprehension of a catalysts’ role during chemical reactions can be understood from the concept of reaction mechanisms and energy diagrams.
03:12Batteries and Fuel Cells
A battery is a galvanic cell that is used as a source of electrical power for specific applications. Modern batteries exist in a multitude of forms to accommodate various applications, from tiny button batteries such as those that power wristwatches to the very large batteries used to supply backup energy to municipal power grids. Some batteries are designed for single-use applications and cannot be recharged (primary cells), while others are based on conveniently reversible cell reactions that...
01:19Oxidation and Reduction of Organic Molecules
Energy production within a cell involves many coordinated chemical pathways. Most of these pathways are combinations of oxidation and reduction reactions, which occur at the same time. An oxidation reaction strips an electron from an atom in a compound, and the addition of this electron to another compound is a reduction reaction. Because oxidation and reduction usually occur together, these pairs of reactions are called redox reactions.
The removal of an electron from a molecule, results in a...
The removal of an electron from a molecule, results in a...
01:43Electron Transport Chain: Complex III and IV
During the electron transport chain, electrons from NADH and FADH2 are first transferred to complexes I and II, respectively. These two complexes then transfer the electrons to ubiquinol, which carries them further to complex III. Complex III passes the electrons across the intermembrane space to Cyt c, which carries them further to complex IV. Complex IV donates electrons to oxygen and reduces it to water. As electrons pass through complexes I, III, and IV, the energy released aids the pumping...
01:27Catalysis
Catalysis influences the rate of chemical reactions by providing an alternative reaction pathway with lower activation energy. A catalyst speeds up a reaction, but it is not consumed during the process. The fundamental principle of catalysis is the ability of a catalyst to alter the reaction mechanism, often introducing a more efficient pathway than the uncatalyzed process.In a catalyzed reaction, the catalyst participates directly in the reaction mechanism. It interacts with reactants to form...