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Enzymes
  Enzyme classes:
  EC 1: Oxidoreductases
  EC 2: Transferases
    EC 2.1
    EC 2.2
    EC 2.3
    EC 2.4
    EC 2.5
    EC 2.6
    EC 2.7
    EC 2.8
    EC 2.9
  EC 3: Hydrolases
  EC 4: Lyases
  EC 5: Isomerases
  EC 6: Ligases
  General information:
  Catalytic mechanism
  Enzyme kinetics
  Inhibitors
  Enzymes in industry

EC 2. Transferase, Nomenclature

Transferase definition

According to the Nomenclature Committee of the International Union of Biochemistry and Molecular Biology (NC-IUBMB) classification, EC 2 Transferases are enzymes that catalyse, or speed up, the transfer of a chemical group from one compound (donor) to another compound (acceptor). It is important to remember, that in many cases transferase donor is cofactor, or coenzyme, carrying the group to be transferred. A very basic reaction catalysed by transferase can be described in the following diagram:

A-X + B -> A + B-X

It started off with the A attached to the X with B added in the reaction. Those are the two reactants. However, when the catalyst is added and the reaction proceeds, the X is removed from the A faster than it normally would be without an enzyme and then transferred to the B. This reaction is used to make a name for all this class of enzymes. Transfer - is a first part of the word transferase, and the second part of the word -ase is common part for all enzymes.

Transferases are belongs to the EC 2 category and can classified further according to recommendation of Nomenclature Committee of the International Union of Biochemistry and Molecular Biology (NC-IUBMB).

EC number classification of Transferases.

EC 2.1 - Enzymes that transfer any one-carbon groups. One example of this would be methyltransferase which catalyzes a reaction that transfers a methyl from the donor to the acceptor.
EC 2.2 - Enzymes that transfer any ketone or aldehyde groups.
EC 2.3 - These include acyltransferase which catalyze the transfer of acyl groups.
EC 2.4 - These include glycosyltransferase which catalyze the transfer of a monosaccharide sugar from an activate sugar phosphate to an acceptor molecule.
EC 2.5 - Enzymes that transfer alkyl or aryl groups diferent from methyl groups.
EC 2.6 - Enzymes that transfer nitrogenous groups. One particular example of this is a transaminase which catalyzes a reaction between an amino acid and an α-keto acid.
EC 2.7 - Enzymes that transfer groups that contain phosphorous. This is commonly called phosphotransferase which also includes polymerase and kinase.
EC 2.8 - Enzymes that transfer groups that contain sulfur. Two examples of this are Sulfurtransferases and sulfotransferase.
EC 2.9 - Enzymes that transfer groups that contain selenium.

The nomenclature for transferases according to International Union of Biochemistry and Molecular Biology (IUBMB) define the standard names for transferases as folows: "donor:acceptor grouptransferase" However, that is a lot to work with and when you are dealing with very long donors or acceptors, it becomes easier to use the common names which are just "donor grouptransferase" or "acceptor grouptransferase". The historical names are also acceptable.

For example, let us consider enzyme aspartate carbamoyltransferase, EC 2.1.3.2. This enzyme catalyse following reaction:
carbamoyl phosphate + L-aspartate -> phosphate + N-carbamoyl-L-aspartate

Systematic name: carbamoyl-phosphate:L-aspartate carbamoyltransferase
Common names: aspartate carbamyltransferase
Historic name: ATCase