An azadithiolate cofactor is an

anion An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by convent ...

with the formula NH(CH₂S)₂²⁻. It is used as a cofactor in the

eFe Agencia EFE, S.A. () is a Spanish international news agency, the major multimedia news agency in Spanish language and the world's fourth largest wire service after the Associated Press, Reuters, and Agence France-Presse. EFE was created in 1939 ...

hydrogenase A hydrogenase is an enzyme that catalyses the reversible oxidation of molecular hydrogen (H2), as shown below: Hydrogen uptake () is coupled to the reduction of electron acceptors such as oxygen, nitrate, sulfate, carbon dioxide (), and fumara ...

s, bacterial enzymes responsible for the reversible reduction of 2 H⁺ to H₂. As a cofactor, the two

thiolate In organic chemistry, a thiol (; ), or thiol derivative, is any organosulfur compound of the form , where R represents an alkyl or other organic substituent. The functional group itself is referred to as either a thiol group or a sulfhydryl grou ...

functional group In organic chemistry, a functional group is a substituent or moiety in a molecule that causes the molecule's characteristic chemical reactions. The same functional group will undergo the same or similar chemical reactions regardless of the rest ...

s are bound to each of the two irons in the

active site In biology and biochemistry, the active site is the region of an enzyme where substrate molecules bind and undergo a chemical reaction. The active site consists of amino acid residues that form temporary bonds with the substrate (binding site) a ...

of the enzyme in a bridging fashion. The

amine In chemistry, amines (, ) are compounds and functional groups that contain a basic nitrogen atom with a lone pair. Amines are formally derivatives of ammonia (), wherein one or more hydrogen atoms have been replaced by a substituen ...

functional group serves as an acid/base to transfer H⁺ from the solution to the active site. The proton transfer function of this cofactor is of great importance to the activity of the hydrogenase enzyme, as H₂ evolution will not occur if the amine is not present.

References

{{Reflist Cofactors