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Rate Constants and Rate Law definitions

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  • Rate Constant
    A positive value indicating reaction efficiency or probability under specific conditions; higher values mean faster reactions.
  • k1
    Association rate constant for free enzyme and substrate forming the enzyme-substrate complex.
  • k-1
    Dissociation rate constant for the enzyme-substrate complex reverting to free enzyme and substrate.
  • k2
    Rate constant for enzyme-substrate complex dissociating to yield product and free enzyme; often the slowest step.
  • k-2
    Reverse rate constant for product and enzyme associating to reform the enzyme-substrate complex; negligible at reaction start.
  • Enzyme-Substrate Complex
    Intermediate formed when enzyme and substrate associate; central to reaction steps and rate constants.
  • Initial Reaction Velocity
    Measured at the very start of a reaction when product concentration is zero; simplifies analysis by ignoring k-2.
  • Reaction Velocity
    Change in product concentration over time; symbolized as v and central to rate law calculations.
  • Rate Law
    Mathematical relationship linking reaction velocity, rate constant, and initial reactant concentrations.
  • Reaction Order
    Exponent in the rate law, often matching reactant coefficients; must be experimentally determined.
  • Product Formation Step
    Stage in enzyme-catalyzed reactions where the enzyme-substrate complex yields product; governed by k2.
  • Free Enzyme
    Unbound enzyme available to associate with substrate or product; involved in rate constant steps.
  • Free Substrate
    Unbound reactant available to associate with enzyme; participates in forming the enzyme-substrate complex.
  • Product Concentration
    Amount of product present at any time; its change is used to determine reaction velocity.
  • Rate Limiting Step
    Slowest step in a reaction, dictating overall reaction speed; typically associated with k2 in enzyme kinetics.