Sulfation (biology)

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Sulphate group coupled via an ester bond

Sulphation is the process by which a sulpho group is coupled to the oxygen of an OH group on a biomolecule . The reaction thus represents an O- sulfonation. Because the product now contains a sulfate group (sulfuric acid ester), this reaction is often called sulfation, although it is (bio) chemically incorrect. The enzyme-mediated reaction is very specific and is an important post-translational modification of tyrosines in proteins and a step in the biosynthesis of glycosaminoglycans .

properties

The process of sulfation is similar to the process of phosphorylation . Sulfate is irreversibly coupled to a hydroxyl group by enzymes from the group of so-called tyrosine sulfotransferases (sulfotransferases are found in mammals especially in the liver , kidneys , gastrointestinal tract and lungs ). Sulphated biomolecules can be glycoproteins , proteoglycans , glycolipids or small metabolites . The sulfate group comes from the phosphoadenosine phosphosulfate .

Sulphation is particularly important in interactions between cells and with the extracellular matrix . Sulphated glycoproteins and proteoglycans are accordingly located in the cell membrane or are secreted into the extracellular matrix and play a role in cell adhesion and in the presentation and modulation of growth factors , chemokines and other molecules involved in intercellular communication. The sulfate groups contribute to the specificity of the interactions.

In the mammalian organism, the sulphonation of potentially toxic foreign substances by sulfotransferases plays an important role in detoxification . As this makes them more soluble in water, they can be excreted more quickly through the kidneys. Thus, the sulfonation is one of the biotransformation of phase-II , is effected in the coupling of the activated cofactors of the active ingredients. Since during the conjugation of foreign substances, in addition to the "sulfation" of alcohols and phenols ( O- sulfonation), the N- sulfonation of amines also takes place (which produces sulfoamines), the term “sulfation” should not be used here.

literature

  • S. Hemmerich, D. Verdugo, VL Rath: Strategies for drug discovery by targeting sulfation pathways . In: Drug Discov Today . 9 (22), 2004, pp. 967-975. PMID 15539140 .