Sulfotransferase

Sulfotransferases ( EC 2.8.2 -. ) Are enzymes transfer the sulfo groups. They are found in eubacteria and eukaryotes and are divided into membrane-associated and soluble sulfotransferases.

Reaction

Sulfotransferases transfer the sulfo group from the cosubstrate 3'- phosphoadenosine -5'- phosphosulfate ( PAPS ) to acceptor groups such as hydroxyl or amine various substrates. This produces 3'- phosphoadenosine -5'-phosphate (PAP). As often alcohols (R- OH) are sulfonated by sulfotransferases as substrates and thus arise as products sulfate ester (R- OSO 3 ), it is called frequently, but biochemically not entirely correct from a sulfation.

In addition to oxygen functions can, for example, and nitrogen functions are sulfonated: so is Anillin (Ar - NH2) sulfonated by sulfotransferases, which product is the Sulfonamin of aniline (Ar -NH- SO 3 ) is formed and not a sulfate. In animals, enzymes act as a homodimer and heterodimer in plants as a monomer.

Occurrence and function

Because of their occurrence in the cell, the sulfotransferases are divided into two groups. Group 1 form the membrane -associated sulfotransferases accept the macromolecules such as proteins and glycosaminoglycans. Enzymes of this group were found in animals and plants. Members of the second group are soluble sulfotransferases, they accept small organic molecules such as flavonoids, steroids, neurotransmitters and xenobiotics. Members of the second group are subdivided into two groups based on their function. Enzymes of the first subgroup have participated in a function of detoxification, which are the second subgroup of metabolic processes such as the inactivation of steroids. The first group uses a wide range of substrates, the second group, however, is highly specific for its substrate.