Rhodanese

• OMIM: 180370
• UniProt: Q16762

• CAS Number: 9026-04-4

As rhodanese, also sulfur transferase enzymes are called, transfer the sulfur from thiosulfate or persulfide to other molecules. The transfer of persulfide is an important part of the sulfide oxidation, thus detoxifying the constant arising during Cysteinabbau hydrogen sulfide. With the transfer of sulfur on Cyanide these are also detoxifies the body thiocyanates. Transfer to the iron produced functioning as a cofactor iron-sulfur cluster. Rhodanasen are found in many bacteria and fungi. The Rhodanasen of multicellular organisms are localized in the mitochondria and the chloroplasts. The TST man also shows weak Mercaptopyruvat - sulfurtransferase activity.

Rhodanasen among the Sulfurtransferasen.

Catalyzed reaction

The reaction takes place in two steps.

In the first step disulfidic bond is formed in the catalytic site of the enzyme by the sulfur donor, a sulfur atom to be transferred to the thiol group in the cysteine ​​residue C247 to form a disulphane.

In the second step, the substrate is sulfided to regenerate the thiol group.

The main substrate is the persulfide sulfide: quinone oxidoreductase, which delivers the sulfur, which is transmitted in the second step to sulfite, which is to thiosulfate.

In the less important Cyanidsulfurierung thiosulfate is the donor and the acceptor cyanide of the sulfur atom:

The effectiveness of thiosulfate (e.g., in the form of a sodium thiosulfate solution ) at cyanide poisoning is also based on the activation of this enzymatic detoxification system.

Rhodanese as a domain

The amino acids 25-143 and 173-288 ( at start -Met as 1) each form a catalytic protein domain which is also found in several other proteins, such as Mercaptopyruvat Sulfurtransferase - and M- phase inducer phosphatases.