There are thousands of different enzymes and each one is specific to the reaction which it catalyzes. Enzymes have names which show what they do. Enzyme names usually end in –ase to show that they are enzymes. Examples of this include ATP synthase. It makes a chemical called ATP. Another example is DNA polymerase. It reads an intact DNA strand and uses it as a template to make a new strand.
One example of an enzyme is amylase, found in saliva. It breaks down starch molecules into smaller glucose and maltose molecules. Another kind of enzyme is lipase. It breaks down fats into smaller molecules, fatty acids and glycerol.
The proteases are a whole class of enzymes. They break down other enzymes and proteins back into amino acids. Nucleases are enzymes that cut DNA or RNA, often in specific place in the molecule.
Enzymes are not only for breaking large chemicals into smaller chemicals. Other enzymes take smaller chemicals and build them up into bigger chemicals, and do many other chemical tasks.

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