Virtually every one of life s chemical reactions is driven by some enzyme. Enzymes are organic catalysts that work like a starter on a car. With a small input of energy from the starter, a car can run on its own energy all day. Enzymes are not used up or changed when they jumpstart another molecule. They can perform the same task over and over.
Enzymes work very fast.
They can carry out their task thousands of times per second. Each enzyme has its own unique structural shape which allows it to bind to or unlock certain other molecules called substrates. When the correct lock and key come together, a chemical bond is formed. This event may help regulate a biochemical process or it may be one step in a sequence of programmed events. When a mutation occurs in a gene that encodes an enzyme, the structural shape of the enzyme is often changed.