Rate-determining step

The step in a multistep reaction mechanism that most strongly limits the overall reaction rate under specified conditions. It need not be the slowest elementary step in every kinetic regime.

Chemical reaction mechanism: A sequence of elementary steps describing how reactants transform into products. The rate-determining step is identified within a proposed mechanism.
Chemical kinetics: The study of reaction rates and how they depend on conditions and molecular processes. The rate-determining step is a kinetic claim about the overall reaction.
Rate-limiting step: A step or process whose capacity constrains the throughput of a larger system. In chemistry it is often used like “rate-determining step,” but the terms can carry different meanings across fields.
Catalysis: The acceleration of a chemical reaction by a substance regenerated during the reaction. Catalysts change pathway barriers and can shift which step controls turnover.
Microkinetic modeling: A computational approach that predicts reaction behavior from a network of elementary steps and their rate constants. It can reveal multiple influential steps where a single-step bottleneck picture fails.
Elementary reaction: A single molecular event represented by one step in a reaction mechanism. Its molecularity and rate law help determine whether it limits the full sequence.
Rate law: An equation relating a reaction rate to reactant concentrations and, often, a rate constant. The observed rate law can reveal which mechanistic steps influence the measured rate.
Turnover-limiting step: A catalytic-cycle step that most constrains catalyst turnover under specified conditions. Catalytic cycles can have changing bottlenecks, so a single fixed slowest step may mislead.
Enzyme catalysis: The acceleration of biochemical reactions by enzymes through specific molecular interactions. Enzyme cycles often change their turnover-limiting step with substrate concentration or conditions.
Degree of rate control: A sensitivity measure describing how strongly a reaction rate responds to changing an elementary step’s rate constant. It quantifies rate influence without forcing every mechanism into one uniquely slow step.

Linked from 7 pages