biostudies-literatureHexter SVBiotechnology and Biological Sciences Research Council11516-21https://www.ebi.ac.uk/biostudies/studies/S-EPMC3406873biostudies-literatureUnknown109(29)The extraordinary ability of Fe- and Ni-containing enzymes to catalyze rapid and efficient H(+)/H(2) interconversion--a property otherwise exclusive to platinum metals--has been investigated in a series of experiments combining variable-temperature protein film voltammetry with mathematical modeling. The results highlight important differences between the catalytic performance of [FeFe]-hydrogenases and [NiFe]-hydrogenases and justify a simple model for reversible catalytic electron flow in enzymes and electrocatalysts that should be widely applicable in fields as diverse as electrochemistry, catalysis, and bioenergetics. The active site of [FeFe]-hydrogenases, an intricate Fe-carbonyl complex known as the "H cluster," emerges as a supreme catalyst.Proceedings of the National Academy of Sciences of the United States of AmericaElectrocatalytic mechanism of reversible hydrogen cycling by enzymes and distinctions between the major classes of hydrogenases.PMC3406873BB/I022309-1H003878-1Armstrong FAHappe THexter SVGrey FCliment VfalseElectrocatalytic mechanism of reversible hydrogen cycling by enzymes and distinctions between the major classes of hydrogenases.The extraordinary ability of Fe- and Ni-containing enzymes to catalyze rapid and efficient H(+)/H(2) interconversion--a property otherwise exclusive to platinum metals--has been investigated in a series of experiments combining variable-temperature protein film voltammetry with mathematical modeling. The results highlight important differences between the catalytic performance of [FeFe]-hydrogenases and [NiFe]-hydrogenases and justify a simple model for reversible catalytic electron flow in enzymes and electrocatalysts that should be widely applicable in fields as diverse as electrochemistry, catalysis, and bioenergetics. The active site of [FeFe]-hydrogenases, an intricate Fe-carbonyl complex known as the "H cluster," emerges as a supreme catalyst.2012-01-01T00:00:00Z2012 Jul2025-04-19T02:53:50.216Z2019-03-27T00:56:03ZS-EPMC34068732280267510.1073/pnas.1204770109