What happens to an enzyme after a biochemical reaction?

Therefore, the rate of most biochemical reactions must be increased by a catalyst. A catalyst is a chemical that speeds up chemical reactions. In organisms, catalysts are called enzymes. Like other catalysts, enzymes are not reactants in the reactions they control. Dec 5, 2014

Nothing--enzymes make reactions go faster (catalyze reactions), but once the reaction is complete the enzyme is just like it was before the reaction.