what happens to an enzyme after it catalyzes
Enzymes are not used up in a chemical reaction. Usually, the enzyme will reset and be ready to use in another reaction. This is due to the fact that enzymes are proteins, and their shape is what they use in a chemical reaction. Initially, the enzyme has a particular shape. Something happens to the enzyme (usually a shape change, called a conformation change, brought on by the presence of two or more chemical reactants), and the enzyme catalyzes the reaction. After the reaction is catalyzed, the product is released, and the enzyme can relax. This means it goes back to its normal shape, ready to do it all over again.