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Related Concept Videos

Enzyme Kinetics01:19

Enzyme Kinetics

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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.
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Introduction to Enzyme Kinetics01:19

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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.
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Reaction Mechanisms: Rate-limiting Step Approximation01:29

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The rate-determining step, or RDS, in a chemical reaction is the slowest step that determines the overall reaction rate. It is identified by using the observed rate law and typically involves approximation methods like the RDS approximation or the steady-state approximation.In the RDS approximation, also known as the rate-limiting-step or equilibrium approximation, the reaction mechanism consists of one or more reversible reactions near equilibrium, followed by a slower RDS, and then one or...
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Catalytically Perfect Enzymes01:07

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Enzymes02:34

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Inside living organisms, enzymes act as catalysts for many biochemical reactions involved in cellular metabolism. The role of enzymes is to reduce the activation energies of biochemical reactions by forming complexes with its substrates. The lowering of activation energies favor an increase in the rates of biochemical reactions.
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Enzymes and Activation Energy01:13

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Phase Space Bottlenecks in Enzymatic Reactions.

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Researchers redefined the transition state by analyzing enzyme dynamics. They discovered a phase space dividing surface occurs earlier than previously thought, refining our understanding of reaction mechanisms.

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Area of Science:

  • Chemical Dynamics
  • Biophysical Chemistry
  • Computational Chemistry

Background:

  • The transition state is crucial for understanding chemical reactions.
  • Previous methods approximated transition states in configuration space.
  • Enzyme reactions involve complex dynamics, including fast motions.

Purpose of the Study:

  • To refine the definition of a transition state on individual reactive trajectories.
  • To investigate a fast subpicosecond motion in an enzyme reaction.
  • To expand transition state definitions beyond configuration space approximations.

Main Methods:

  • Committor analysis on individual reactive trajectories.
  • Time-series analysis to pinpoint motion initiation.
  • Modified committor analysis within transition path sampling.
  • Phase space analysis to identify dynamic events.

Main Results:

  • Identified the precise timing of enzyme-initiated donor-acceptor compression.
  • Located a dividing surface in phase space.
  • Found this phase space dividing surface precedes the configurationally defined transition state.

Conclusions:

  • The definition of a transition state can be more accurately determined using phase space analysis.
  • Fast internal motions play a critical role in enzyme catalysis.
  • This refined approach enhances the understanding of reaction dynamics and enzyme mechanisms.