Transferases

Transferases are a broad group of enzymes that catalyze the transfer of a functional group from one molecule (the donor) to another (the acceptor). They are classified as EC class 2 in enzyme nomenclature and participate in a wide range of essential biochemical processes by modifying substrates rather than adding or removing atoms from scratch.

The most common transfer reactions involve groups such as methyl, glycosyl, acyl, amino, phosphate, or sulfate. Examples of major transferase subfamilies include:

- Methyltransferases, which transfer methyl groups, often using S-adenosyl-L-methionine as the methyl donor.

- Glycosyltransferases, which transfer sugar moieties from activated donors (such as UDP-sugars) to acceptors including proteins, lipids, or small molecules.

- Acyltransferases, which transfer acyl groups from donor molecules such as acyl-CoA to acceptors.

- Aminotransferases (transaminases), which transfer amino groups between amino acids and α-keto acids; these enzymes commonly rely on pyridoxal phosphate as a cofactor.

- Phosphotransferases (including protein kinases), which transfer phosphate groups from ATP or other donors to substrates, playing central roles in metabolism and signaling.

- Sulfotransferases, which transfer sulfate groups from the donor PAPS to various substrates.

Mechanistically, transferases typically require specific cofactors or activated donors and often operate with stringent substrate specificity, recognizing both donor and acceptor molecules. They are integral to metabolism, enabling the biosynthesis and modification of nucleotides, lipids, carbohydrates, proteins, and small molecules. Post-translational modification by transferases, such as phosphorylation or glycosylation, regulates protein activity, localization, and interactions. Transferases are also important in drug metabolism, industrial biocatalysis, and biotechnological applications aiming to synthesize complex biomolecules.

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