The induced-fit model proposes that the initial interaction between enzyme and substrate is relatively weak, but that these weak interactions rapidly induce conformational changes in the enzyme that strengthen binding.
For many years, scientists thought that enzyme-substrate binding took place in a simple “lock-and-key” fashion. This model asserted that the enzyme and substrate fit together perfectly in one instantaneous step. However, current research supports a more refined view called induced fit. As the enzyme and substrate come together, their interaction causes a mild shift in the enzyme’s structure that confirms an ideal binding arrangement between the enzyme and the substrate. This dynamic binding maximizes the enzyme’s ability to catalyze its reaction.
Practice Questions
Khan Academy
MCAT Official Prep (AAMC)
Section Bank C/P Section Question 47
Key Points
• The enzyme‘s active site binds to the substrate
• The induced-fit model states a substrate binds to an active site and both change shape slightly, creating an ideal fit for catalysis.
• Enzymes promote chemical reactions by bringing substrates together in an optimal orientation, thus creating an ideal chemical environment for the reaction to occur.
Key Terms
lock-and-key: A model that asserts an enzyme and substrate fit together perfectly in one instantaneous step.
enzyme: A substance produced by a living organism which acts as a catalyst to bring about a specific biochemical reaction.
substrate: A reactant in a chemical reaction is called a substrate when acted upon by an enzyme.
induced fit: Proposes that the initial interaction between enzyme and substrate is relatively weak, but that these weak interactions rapidly induce conformational changes in the enzyme that strengthen binding.
catalyze: Cause or accelerate (a reaction) by acting as a catalyst.
