Date: Spring 2011
What rules are used in naming enzymes?
Go to http://www.google.com and search for "enzyme naming convention" and
find this Wikipedia article:
that says in paragraph 10:
An enzyme's name is often derived from its substrate or the chemical
reaction it catalyzes, with the word ending in -ase. Examples are lactase,
alcohol dehydrogenase and DNA polymerase. This may result in different
enzymes, called isozymes, with the same function having the same basic name.
Isoenzymes have a different amino acid sequence and might be distinguished
by their optimal pH, kinetic properties or immunologically. Isoenzyme and
isozyme are homologous proteins. Furthermore, the normal physiological
reaction an enzyme catalyzes may not be the same as under artificial
conditions. This can result in the same enzyme being identified with two
different names. E.g. Glucose isomerase, used industrially to convert
glucose into the sweetener fructose, is a xylose isomerase in vivo.
The International Union of Biochemistry and Molecular Biology have developed
a nomenclature for enzymes, the EC numbers; each enzyme is described by a
sequence of four numbers preceded by "EC". The first number broadly
classifies the enzyme based on its mechanism.
The top-level classification is
* EC 1 Oxidoreductases: catalyze oxidation/reduction reactions
* EC 2 Transferases: transfer a functional group (e.g. a methyl or phosphate group)
* EC 3 Hydrolases: catalyze the hydrolysis of various bonds
* EC 4 Lyases: cleave various bonds by means other than hydrolysis and oxidation
* EC 5 Isomerases: catalyze isomerization changes within a single molecule
* EC 6 Ligases: join two molecules with covalent bonds.
The complete nomenclature can be browsed at
According to the naming conventions, enzymes are generally classified into
six main family classes and many sub-family classes. Some web-servers, e.g.,
EzyPred  and bioinformatics tools have been developed to predict which
main family class  and sub-family class   an enzyme molecule
belongs to according to its sequence information alone via the pseudo amino
Commonly, enzymes are named after their function, and end with "ase",
such as "DNA polymerase", which polymerizes DNA.
There's a formal naming convention as well:
And here's a link to some history of enzyme naming:
Hope this helps,
Click here to return to the Molecular Biology Archives
Update: June 2012