7.10:
Induced-fit Model
The interaction of an enzyme with its substrate is highly specific, which means that the enzyme can only bind certain substrates.
This specificity is determined by the shape and chemical characteristics of the active site— the region of the enzyme that binds to the substrate.
Induced fit is a widely accepted model to explain enzyme specificity and catalysis. Unlike the lock-and-key model, which hypothesizes that the substrate fits into the enzyme's active site, the induced-fit model proposes that the enzyme undergoes a change in its three-dimensional shape upon substrate binding.
This conformational change alters the relative positions of specific amino acids of the enzyme to increase their interactions with the substrate. The enzyme-substrate interaction lowers the activation energy for the reaction, increasing the reaction rate.
After the product of the reaction is formed and released from the active site, the enzyme reverts to its original shape and can catalyze additional rounds of the reaction.
7.10:
Induced-fit Model
Most chemical reactions in cells require enzymes—biological catalysts that speed up the reaction without being consumed or permanently changed. They reduce the activation energy needed to convert the reactants into products. Enzymes are proteins, that usually work by binding to a substrate—a reactant molecule that they act upon.
Enzymes exhibit substrate specificity, meaning that they can only bind to certain substrates. This is mainly determined by the shape and chemical characteristics of their active site—the region of the enzyme that binds to the substrate.
According to the induced-fit model of enzyme activity, this binding changes the conformation—or shape—of the enzyme. This brings the substrate closer to the higher energy transition state needed for the reaction to occur, for instance, by weakening its bonds so that it can more readily react. Enzymes may also speed up a reaction by creating conditions within the active site that are more conducive for the reaction to occur than the surrounding cellular environment.
Once the products of the reaction are formed, they are released from the active site of the enzyme, and the enzyme can catalyze reactions once again.