Answer:
The correct answer is "At the active site."
Step-by-step explanation:
Enzymes are proteins that catalyze chemical reactions. The active site of an enzyme is the specific region where the substrate binds and the chemical reaction takes place. Certain amino acids located in the active site play a crucial role in catalyzing the reaction by positioning the substrate correctly and facilitating the formation of chemical bonds. These amino acids are usually found on the surface of the protein, and their specific arrangement and chemical properties are crucial for the enzyme's activity.