Enzymes are highly selective catalysts, meaning that each enzyme only speeds up a specific reaction. [What Is Chemistry?] The molecules that an enzyme works with are called substrates. The substrates bind to a region on the enzyme called the active site.

Do enzymes only work with substrates?

Enzymes are proteins that act as biological catalysts - this means they speed up reactions without being used up. ... An enzyme's active site and its substrate are complementary in shape. An enzyme will only work on one substrate - it is substrate specific. Enzymes and substrates collide to form enzyme-substrate complexes.

Can enzymes only catalyze?

Enzymes are highly specific both in the reactions that they catalyze and in their choice of reactants, which are called substrates. An enzyme usually catalyzes a single chemical reaction or a set of closely related reactions.