What do enzymes change shape when they bind to?

Enzymes change shape when they bind to substrates due to a mechanism known as the "induced fit model." This model suggests that the binding of a substrate to an enzyme's active site causes a conformational change in the enzyme's structure, allowing for a more optimal interaction. This change in shape enhances the enzyme's ability to catalyze the chemical reaction involving the substrate, thereby increasing the efficiency of the biochemical process.

The active site is the specific region of the enzyme where the substrate binds, but it is the substrate itself that initiates the shape change as it fits into the active site. After the reaction has occurred, the products will leave the enzyme, but they do not cause a shape change during their binding. Coenzymes can assist enzymes during the reaction but are not the specific molecules that cause the change in shape of the enzyme. Understanding the role of substrates in enzyme function is critical in biochemistry and helps clarify how enzymes operate as biological catalysts.