The part of an enzyme that binds with the substrate is called the active site. The active site is a specific region of the enzyme that is responsible for catalyzing the chemical reaction that the enzyme performs. The active site contains amino acid residues that interact with the substrate and facilitate the reaction. These amino acid residues are arranged in a specific way to create a pocket or cleft that is complementary to the substrate. The substrate binds to the active site through various types of interactions such as hydrogen bonding, ionic bonding, van der Waals forces, and hydrophobic interactions. The binding of the substrate to the active site induces conformational changes in the enzyme, which bring the catalytic groups of the enzyme into close proximity with the substrate. This allows the enzyme to catalyze the chemical reaction and convert the substrate into products.