Substrate specificity refers to the ability of an enzyme to selectively bind and react with a specific substrate molecule. Enzymes are highly specific in their interactions with substrates, meaning that each enzyme is designed to catalyze a particular chemical reaction involving a specific substrate. This specificity is due to the unique shape and chemical properties of the enzyme's active site, which is perfectly complementary to the structure of the substrate molecule. Understanding substrate specificity is crucial for determining the function of enzymes and how they can be used in various biological processes and applications. Additionally, studying substrate specificity can provide insights into the evolution of enzymes and the role of protein structure in enzyme activity.