Azadithiolate cofactor

An azadithiolate cofactor is an anion with the formula NH(CH₂S)₂²⁻. It is used as a cofactor in the [FeFe] hydrogenases, bacterial enzymes responsible for the reversible reduction of 2 H⁺ to H₂.^[1] As a cofactor, the two thiolate functional groups are bound to each of the two irons in the active site of the enzyme in a bridging fashion. The amine 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

^ Berggren, G.; Adamska, A.; Lambertz, C.; Simmons, T. R.; Esselborn, J.; Atta, A.; Gambarelli, S.; Mouesca, J.-M.; Reijerse, E.; Lubitz, W.; Happe, T.; Artero, V.; Fontecave, M. (2013). "Biomimetic assembly and activiation of [FeFe]-hydrogenases". Nature. 499: 66. doi:10.1038/nature12239.

[1] Berggren, G.; Adamska, A.; Lambertz, C.; Simmons, T. R.; Esselborn, J.; Atta, A.; Gambarelli, S.; Mouesca, J.-M.; Reijerse, E.; Lubitz, W.; Happe, T.; Artero, V.; Fontecave, M. (2013). "Biomimetic assembly and activiation of [FeFe]-hydrogenases". Nature. 499: 66. doi:10.1038/nature12239.

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