sulfotransferase activity

Definition

Target type: molecularfunction

Catalysis of the transfer of a sulfate group from 3'-phosphoadenosine 5'-phosphosulfate to the hydroxyl group of an acceptor, producing the sulfated derivative and 3'-phosphoadenosine 5'-phosphate. [GOC:curators]

Sulfotransferase activity is a crucial biochemical process that involves the transfer of a sulfonate group (SO3-) from a donor molecule, typically 3'-phosphoadenosine 5'-phosphosulfate (PAPS), to an acceptor molecule. This process is catalyzed by a family of enzymes known as sulfotransferases.

Sulfotransferases play a vital role in various cellular processes, including detoxification, signal transduction, and the biosynthesis of bioactive compounds.

**Detoxification:** Sulfotransferases contribute to detoxification by converting harmful substances, such as xenobiotics (foreign chemicals), into more water-soluble forms, facilitating their excretion.

**Signal Transduction:** Sulfotransferases modify signaling molecules, such as hormones and neurotransmitters, influencing their activity and duration of action. For instance, sulfotransferases regulate the activity of steroid hormones, influencing their signaling pathways.

**Biosynthesis of Bioactive Compounds:** Sulfotransferases are involved in the synthesis of various bioactive compounds, including bile acids, heparin, and chondroitin sulfate. These compounds play essential roles in digestion, blood coagulation, and connective tissue structure, respectively.

The molecular mechanism of sulfotransferase activity involves a two-step reaction:

1. **Binding of both PAPS and the acceptor molecule to the enzyme's active site.** This binding event brings the donor and acceptor molecules into close proximity, facilitating the transfer reaction.

2. **Transfer of the sulfonate group from PAPS to the acceptor molecule.** This transfer is a nucleophilic attack, where the acceptor molecule's nucleophile attacks the sulfonate group on PAPS, resulting in the formation of a sulfoconjugate and adenosine 3',5'-bisphosphate (PAP).

The specificity of sulfotransferases for their substrates is determined by the amino acid residues lining their active sites. These residues interact with the substrate molecules, facilitating their binding and promoting the transfer reaction.

Sulfotransferases are essential enzymes involved in various biological processes, making them key players in maintaining cellular homeostasis and organismal health. Their activity is tightly regulated by factors such as substrate concentration, pH, and cofactor availability.'
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Proteins (3)

Compounds (10)