4. Where do substrates attach to an enzyme?* peptide bond
ring binding site
active site
enzymatic site

A substance that speeds up a chemical reaction—without being a reactant—is called a catalyst. The catalysts for biochemical reactions that happen in living organisms are called enzymes. Enzymes are usually proteins, though some ribonucleic acid (RNA) molecules act as enzymes too.

Explanation:

enzymes don't change their own reaction. That's because they don't affect the free energy of reactants or the products.

the answer is :