The enzyme’s active site refers to a small part of the enzyme where the substrate molecules bind and a chemical reaction occurs. 

The active site of an enzyme is a three-dimensional cleft or crevice that’s composed of various amino acid sequences. It occupies a small portion of the total volume of the enzyme. 

Substrates bind to enzymes at the active site through multiple weak attractions. The precise arrangement of atoms in the enzyme’s active site determines binding specificity.