2026/04/18 by Carolina Garcia Garcia, Max Brabender, William F. Martin · 2 voices
Energy · Physics and Astronomy · Biochemistry, Genetics and Molecular Biology · #Metalloenzymes and iron-sulfur proteins #Origins and Evolution of Life #Porphyrin Metabolism and Disorders
paper · doi:10.1111/febs.70556
openalex publication_date 2026/04/18 · openalex created_date 2026/04/19 · openalex updated_date 2026/05/21
Compared to iron, nickel is comparatively rare as a transition metal in enzymes. However, it is essential in several enzymes of carbon and energy metabolism in acetogens (bacteria) and methanogens (archaea), which use the acetyl‐CoA pathway of H 2 ‐dependent CO 2 fixation. Nickel containing enzymes of acetogens and methanogens include FeNi hydrogenase, carbon monoxide dehydrogenase, acetyl‐CoA synthase and, in methanogens, methyl‐CoM reductase in the last step of methane synthesis. Several lines of evidence implicate the acetyl‐CoA pathway as the most ancient pathway of CO 2 fixation, most notably recent findings that the overall reaction of the enzymatic pathway from H 2 ( E 0 ′ = −414 mV) and CO 2 to pyruvate can be replaced by Ni 0 alone in water as the lone catalyst. Here, we studied Ni 0 as a catalyst and reductant for nonenzymatic redox reactions that require only a mild reductant, as the midpoint potential of Ni 0 oxidation to Ni 2+ is E 0 ′ = −260 mV. We showed that Ni 0 in water can convert 2‐oxo acids to 2‐hydroxy acids and, in the presence of NH 3 , to amino acids at 25–100 °C without the addition of H 2 , and that it functions as a catalyst and reductant for the fumarate reductase reaction. The findings expand the repertoire of ancient metabolic reactions that Ni 0 can catalyze without proteins, cofactors, or sulfur, shedding light on the broad catalytic activity and substrate specificity of Ni 0 at metabolic origin.