Hydrolytic enzymes break down protein, carbohydrate, and fat molecules into their simplest units. The hydrolysis of polymers by hydrolytic enzymes results in free monomers.

During hydrolysis (hydro-,"water";lysis-,"break") a water molecule is added to the polymer and cleaves the covalent bond holding the two monomers. The reverse of a hydrolysis reaction is a condensation reaction.