Video Experimental Relacionado
Updated: Jul 8, 2026
09:42
Unraveling Entropic Rate Acceleration Induced by Solvent Dynamics in Membrane Enzymes
Published on: January 16, 2016
Un análisis teórico de las constantes de velocidad y los efectos cinéticos de los isótopos correspondientes a
Silvia Ferrer1, Iñaki Tuñón, Sergio Martí
1Departament de Química Física, Universitat de València, València, Spain.
Journal of the American Chemical Society
|December 21, 2006
Resumen
El análisis computacional de la lactato deshidrogenasa revela cómo la dinámica del sitio activo de la enzima influye en las tasas de reacción. Diferentes complejos de reactivos conducen a velocidades catalíticas variadas, validadas por efectos de isótopos cinéticos.
Área de la Ciencia:
- La bioquímica es la bioquímica.
- Química computacional es la química computacional.
- Enzimología Enzimología.
Sus antecedentes:
- Las reacciones enzimáticas pueden exhibir constantes de velocidad variables debido a cambios conformacionales acoplados al paso químico.
- Los experimentos de una sola molécula revelan una dispersión constante de velocidad vinculada a diferentes valles de reactivos.
Objetivo del estudio:
- Para investigar computacionalmente la transformación de piruvato a lactato catalizada por la lactato deshidrogenasa.
- Comprender cómo la dinámica del sitio activo y las variaciones complejas de los reactivos afectan las velocidades y los mecanismos de reacción.
Principales métodos:
- Técnicas de perturbación de energía libre para estimar las constantes de velocidad a lo largo de las coordenadas de reacción intrínsecas.
- Teoría del estado de transición variacional promedio de conjunto con túnel multidimensional para efectos de túnel.
- Análisis de la disposición de residuos en el sitio activo, las interacciones con el sustrato y la presencia de moléculas de agua.
Principales resultados:
- El cierre del sitio activo de la lactato deshidrogenasa por un bucle flexible forma complejos de reactivos distintos.
- Estos complejos exhiben variaciones en los arreglos clave de residuos (por ejemplo, Arg109), interacciones de sustrato e hidratación.
- El paso químico procede a diferentes velocidades dependiendo del complejo de reactivos específico, influenciado por la asincronicidad y las barreras energéticas.
- Los efectos de isótopos cinéticos primarios calculados se alinean bien con los datos experimentales.
Conclusiones:
- La flexibilidad del sitio activo de la enzima y los estados conformacionales resultantes son determinantes críticos de la eficiencia catalítica.
- La metodología computacional empleada está validada por su acuerdo con los efectos experimentales de isótopos cinéticos.
- Comprender estas dinámicas proporciona información sobre la catálisis enzimática y la modulación de la velocidad de reacción.
Videos de Conceptos Relacionados
01:19Enzyme Kinetics
Enzymes speed up reactions by lowering the activation energy of the reactants. The speed at which the enzyme turns reactants into products is called the rate of reaction. Several factors impact the rate of reaction, including the number of available reactants. Enzyme kinetics is the study of how an enzyme changes the rate of a reaction.
Scientists typically study enzyme kinetics with a fixed amount of enzyme in the controlled environment of a test tube. When more reactant, or substrate, is...
Scientists typically study enzyme kinetics with a fixed amount of enzyme in the controlled environment of a test tube. When more reactant, or substrate, is...
02:53Reaction Rate
The rate of reaction is the change in the amount of a reactant or product per unit time. Reaction rates are therefore determined by measuring the time dependence of some property that can be related to reactant or product amounts. Rates of reactions that consume or produce gaseous substances, for example, are conveniently determined by measuring changes in volume or pressure.
The mathematical representation of the change in the concentration of reactants and products, over time, is the rate...
The mathematical representation of the change in the concentration of reactants and products, over time, is the rate...
01:19Introduction to Enzyme Kinetics
Enzyme kinetics studies the rates of biochemical reactions. Scientists monitor the reaction rates for a particular enzymatic reaction at various substrate concentrations. Additional trials with inhibitors or other molecules that affect the reaction rate may also be performed.
The experimenter can then plot the initial reaction rate or velocity (Vo) of a given trial against the substrate concentration ([S]) to obtain a graph of the reaction properties. For many enzymatic reactions involving a...
The experimenter can then plot the initial reaction rate or velocity (Vo) of a given trial against the substrate concentration ([S]) to obtain a graph of the reaction properties. For many enzymatic reactions involving a...
01:22Factors Influencing the Rate of Chemical Reactions
A variety of factors influence the rate of chemical reactions. For a chemical reaction to happen, atoms must collide with enough energy to overcome the repulsion between their electrons. This energy is called activation energy. Factors influencing the rate of reaction either lower the activation energy or increase the likelihood of a successful collision.
Concentration and Pressure:
The more particles present within a given space, the more likely those particles are to bump into one another.
Concentration and Pressure:
The more particles present within a given space, the more likely those particles are to bump into one another.
01:17Factors Affecting Activity Coefficient
The extended Debye-Hückel equation indicates that the activity coefficient of an ion in an aqueous solution at 25°C depends on three partially interdependent properties: the ionic strength of the solution, the charge of the ion, and the ion size.
The activity coefficient value for an ion is close to one when the solution has almost zero ionic strength, i.e., when the solution shows close to ideal behavior. As the ionic strength of the solution increases from 0 to 0.1 mol/L, a decrease in the...
The activity coefficient value for an ion is close to one when the solution has almost zero ionic strength, i.e., when the solution shows close to ideal behavior. As the ionic strength of the solution increases from 0 to 0.1 mol/L, a decrease in the...
01:27Fast Reactions
Fast reactions occurring in times shorter than the time needed to mix reactants pose a unique challenge for investigation. In a liquid-phase continuous-flow system, reactants A and B are swiftly pushed into the mixing chamber, where mixing occurs within 1 ms. The reaction mixture then flows through an observation tube, and one measures light absorption to determine species concentrations at various points of the tube. This method is most appropriate when relatively large volumes of reactants...