Naming Conventions for Enzymes

Virtually all enzymes are proteins, made up of amino acids (as are all other proteins). As in many areas in science, the naming of enzymes follows some general guidelines and rules, which can help you understand their origin and purpose.

Early on in their study, enzymes were given names ending in the letters -in. Some examples are trypsin, rennin (familiar for its use in making cheese ), pepsin and chymotrypsin. Most of the enzymes with the -in ending are pancreatic enzymes, since those were the one that were identified first.

Later, the practice shifted to naming newly discovered enzymes with an ending of -ase. This convention is applied to both metabolic (systemic) as well as digestive enzymes. This is perhaps a more helpful construct, because the part of the name preceding the -ase indicates the type of substance on which the enzyme acts.

For example, the chemical names for different types of sugars usually end in -ose (for example: lactose, sucrose and fructose). So, you can infer that sucrase is an enzyme which acts on sucrose. Similarly, you could expect that the enzyme lactase acts upon the milk sugar lactose. (In both of these cases, the enzyme action is to break down the substrate upon which it acts.)

Here’s a little more complex example: the metabolic enzyme pyruvate dehydrogenase is found to act upon pyruvate. It enzymatic action is to remove a hydrogen molecule – that is to dehydrogenize the pyruvate.

Of course, there are many types of enzymes, besides the digestive types, and not all action involved a simple breakdown of the substrate involved. Enzymes can transfer molecules or combine and build up molecules.