Biochemistry Questions / Discuss the naming conventions for enzymes and the significance of naming enzymes based on their catalytic reactions. How has the transition to EC numbers impacted enzyme classification?

Enzymes were originally named based on the reaction they catalysed: proteolysis – protease, nucleic acid cleavage – nuclease, hydrolysis of starch (amylum) - amylase. This became more complicated as technology advanced and many more enzymes were studied.

Now, enzymes are classified into EC numbers. This is still based on the reaction the enzyme catalyses, but a number (in the format EC x.x.x.x, where x is a number) is allocated. This reduces the likelihood of running out of names – or doing scientist’s favourite thing: giving two different things the same name. Enzymes still have their traditional names in addition to an EC number, so it does not cause complexity in the literature (unlike renaming species).