Enzymes belong to a class of biological molecules known as proteins. The function of an enzyme is to increase the rate of a reaction. Reactions in the cell can take place a million times faster with enzymes.
Enzymes react with one reactant known as a substrate. Naming an enzyme is done by adding the suffix "ase" to the name of the root name of the substrate it is acting upon. For example, the enzyme sucrase catalyzes the hydrolysis of sucrose into glucose and fructose. Enzymes are also classified based on the types of reactions they catalyze. Transferases, for example, catalyze the transfer of functional groups.