TRANSFERASES: PROCESSES, FUNCTIONS, NOMENCLATURE AND SUBCLASSES - BIOLOGY - 2025

The transferases are enzymes that transfer functional groups of a substrate acting as donor to another acting as a receiver. Most of the metabolic processes essential for life involve transferase enzymes.

The first observation of the reactions catalyzed by these enzymes was documented in 1953 by Dr. RK Morton, who observed the transfer of a phosphate group from an alkaline phosphatase to a β-galactosidase that acted as a receptor for the phosphate group.

Glycine N-methyltransferase (Source: Jawahar Swaminathan and MSD staff at the European Bioinformatics Institute via Wikimedia Commons)

The nomenclature of the transferase enzymes is generally made according to the nature of the molecule that accepts the functional group in the reaction, for example: DNA-methyltransferase, Glutathione-transferase, 1,4-α-glucan 6-α-glucosyltransferase, among other.

Transferases are enzymes with biotechnological importance, especially in the food and drug industry. Their genes can be modified to perform specific activities in organisms, thus contributing directly to consumer health, beyond the nutritional benefit.

Prebiotic drugs for the intestinal flora are rich in transferases, since these participate in the formation of carbohydrates that favor the growth and development of beneficial microorganisms in the intestine.

Deficiencies, structural damage and interruptions in the processes catalyzed by transferases cause the accumulation of products within the cell, which is why many different diseases and pathologies are associated with such enzymes.

The malfunction of transferases causes diseases such as galactosemia, Alzheimer's, Huntington's disease, among others.

Biological processes in which they participate

Among the great number of metabolic processes in which transferases participate are the biosynthesis of glycosides and the metabolism of sugars in general.

A glucotransferase enzyme is responsible for the conjugation of A and B antigens on the surface of red blood cells. These variations in antigen binding are caused by a polymorphism of the Pro234Ser amino acids of the original structure of B-transferases.

Glutathione-S-transferase in the liver participates in the detoxification of liver cells, helping to protect them from reactive oxygen species (ROS), free radicals and hydrogen peroxides that accumulate in the cell cytoplasm and are highly toxic.

Glutathione-S-Transferase (Source: Jawahar Swaminathan and MSD staff at the European Bioinformatics Institute via Wikimedia Commons)

Aspartate carbamoyl transferase catalyzes the biosynthesis of pyrimidines in the metabolism of nucleotides, fundamental components of nucleic acids and high-energy molecules used in multiple cellular processes (such as ATP and GTP, for example).

Transferases participate directly in the regulation of many biological processes by silencing by epigenetic mechanisms the DNA sequences that encode the information necessary for the synthesis of cellular elements.

Histone acetyltransferases acetylate conserved lysine residues on histones by transferring an acetyl group from an acetyl-CoA molecule. This acetylation stimulates the activation of transcription associated with the unwinding or relaxation of euchromatin.

Phosphotransferases catalyze the transfer of phosphate groups in probably all cellular metabolic contexts. It has an important role in carbohydrate phosphorylation.

Aminotransferases catalyze the reversible transfer of amino groups from amino acids to oxacids, one of many amino acid transformations mediated by vitamin B6-dependent enzymes.

Features

Transferases catalyze the movement of chemical groups by accomplishing the reaction shown below. In the following equation the letter "X" represents the donor molecule of the functional group "Y" and "Z" acts as the acceptor.

XY + Z = X + YZ

These are enzymes with strong electronegative and nucleophilic elements in their composition; These elements are responsible for the transfer capacity of the enzyme.

The groups mobilized by the transferases are generally aldehyde and ketone residues, acyl, glucosyl, alkyl, nitrogenous and nitrogen-rich groups, phosphorus, sulfur-containing groups, among others.

Nomenclature

The classification of transferases follows the general rules of the classification of enzymes proposed by the Enzyme Commission in 1961. According to the committee, each enzyme receives a numerical code for its classification.

The position of the numbers in the code indicates each of the divisions or categories in the classification and these numbers are preceded by the letters "EC".

In the classification of transferases, the first number represents the enzyme class, the second number symbolizes the type of group they transfer, and the third number refers to the substrate on which they act.

The nomenclature of the class of transferases is EC.2. It has ten subclasses, so there are enzymes with the code from EC.2.1 to EC.2.10. Each denotation of the subclass is made mainly according to the type of group that transfers the enzyme.

Subclasses

The ten classes of enzymes within the transferase family are:

EC.2.1 Transfer groups of a carbon atom

They transfer groups that include a single carbon. Methyltransferase, for example, transfers a methyl group (CH3) to the nitrogenous bases of DNA. The enzymes of this group directly regulate the translation of genes.

EC.2.2 Transfer aldehyde or ketone groups

They mobilize aldehyde groups and ketone groups having saccharides as receptor groups. Carbamyltransferase represents a mechanism of regulation and synthesis of pyrimidines.

EC.2.3 Acyltransferases

These enzymes transfer acyl groups to derivatives of amino acids. Peptidyltransferase performs the essential formation of peptide bonds between adjacent amino acids during the translation process.

EC.2.4 Glycosyltransferases

They catalyze the formation of glycosidic bonds using phosphate sugar groups as donor groups. All living beings present DNA sequences for glycosyltransferases, since they participate in the synthesis of glycolipids and glycoproteins.

EC.2.5 Transfer alkyl or aryl groups apart from methyl groups

They mobilize alkyl or aryl groups (other than CH3) like dimethyl groups, for example. Among them is glutathione transferase, which was mentioned earlier.

EC.2.6 Transfer nitrogen groups

Enzymes of this class transfer nitrogen groups such as -NH2 and -NH. These enzymes include aminotransferases and transaminases.

EC.2.7 Transfer groups containing phosphate groups

They catalyze the phosphorylation of substrates. Generally the substrates of these phosphorylations are sugars and other enzymes. Phosphotransferases transport sugars into the cell, simultaneously phosphorylating them.

EC.2.8 Transfer groups containing sulfur

They are characterized by catalyzing the transfer of groups that contain sulfur in their structure. Coenzyme A transferase belongs to this sub-class.

EC.2.9 Transfer groups containing selenium

They are commonly known as seleniotransferases. These mobilize L-seril groups to transfer RNAs.

EC.2.10 Transfer groups containing either molybdenum or tungsten

The transferases of this group mobilize groups containing molybdenum or tungsten to molecules that have sulfide groups as acceptors.

References

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