Sulfation,
sulfurylation, or sometimes incorrectly described as
sulfonation, in biochemistry is the enzyme-catalyzed conjugation of a
sulfo group (not a
sulfate or
sulfuryl group) to another molecule. This biotransformation involves a
sulfotransferase enzyme catalyzing the transfer of a sulfo group from a donor cosubstrate, usually
3'-phosphoadenosine-5'-phosphosulfate (PAPS), to a substrate molecule's hydroxyl or amine. Sulfation is involved in a variety of biological processes, including detoxification, hormone regulation, molecular recognition, cell signaling, and viral entry into cells. It is among the reactions in
phase II drug metabolism, oftentimes effective in rendering a
xenobiotic less active from a
pharmacological and
toxicological standpoint, but sometimes playing a role in the activation of xenobiotics (e.g.
aromatic amines, methyl-substituted
polycyclic aromatic hydrocarbons). Another example of biological sulfation is in the synthesis of sulfonated
glycosaminoglycans, such as
heparin,
heparan sulfate,
chondroitin sulfate, and
dermatan sulfate. Sulfation is also a possible
posttranslational modification of proteins.
