What is sulfation or sulfonation?
Chemically “sulfation” refers to the conversion of a molecule into a sulfate. More specifically, it is the addition of a sulfate group as an ester group to a target molecule such as a hydroxyl group connected to a hydrophobic moiety.
In chemistry, a sulfate refers to a salt or ester of sulfuric acid. Therefore, sulfation refers to the “combination, treatment, or impregnation of a compound with sulfuric acid, a sulfate, or sulfates. Alternatively it also refers to the “conversion of a molecule or chemical compound to a sulfate”, in electricity it refers to the deposit of a lead-sulfate compound on the lead electrodes of a storage battery. The general meaning is “to become sulfated”.
Alternatively, sulfation refers to the transfer of a sulfate group from 3'-phosphoadenosine 5'-phosphosulfate (PAPS) to a substrate that is catalyzed by a family of sulfotransferase enzymes.
Scientists now know that sulfation is an essential post-translational modification of many molecules including proteins, carbohydrates, and lipids found in eukaryotes. In recent years, it has become apparent that sulfation and sulfotransferases have many important functions in various tissue types.
Early studies that identified phenolic sulfate esters in the urine of humans and animals treated with phenols derived the term “sulfation”. However, when PAPS as the donor of the “active sulfate” group was identified it became apparent that a sulfonate group (-SO3) was being transferred in the reactions rather than a sulfate group. Therefore, the more appropriate term to use is “sulfation” for these sulfonation reactions. On the other hand, sulfonation refers to the attachment of the sulfonic acid group, -SO3H, to a carbon in an organic compound.
The sulfation reaction is dependent on the enzymatic synthesis of an activated sulfate donor. A PAPS synthetase is needed for the synthesis of the sulfate donor 3’-phospho-adenosine 5’-phosphosulfate (PAPS).
A large family of enzymes called sulfotransferases transfers the sulfate group from the donor compound 3’-phosphoadenosine 5’-phosphosulfate to the major acceptor groups. These can be aromatic or aliphatic hydroxyls whose conjugation gives rise to a sulfate moiety. However, sulfotransferases are also capable of conjugating other structural groups, including primary amines, N-oxides, and hydroxyl amines.
Many different biological molecules are substrates for the sulfotransferases and sulfation affects many different physiological processes, including:
1) Deactivation and bioactivation of xenobiotics,
2) Inactivation of hormones and catecholamines,
3) Structure and function of macromolecules, and
4) Elimination of end products of catabolism.
Reference
Klaassen CD, Boles JW.; Sulfation and sulfotransferases 5: the importance of 3'-phosphoadenosine 5'-phosphosulfate (PAPS) in the regulation of sulfation. FASEB J. 1997 May;11(6):404-18.
http://origin-dictionary.reference.com/browse/sulfation
http://origin-dictionary.reference.com/browse/sulfonation?s=t
-.-