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Isotopic fractionation associated with [NiFe]‐ and [FeFe]‐hydrogenases
Author(s) -
Yang Hui,
Gandhi Hasand,
Cornish Adam J.,
Moran James J.,
Kreuzer Helen W.,
Ostrom Nathaniel E.,
Hegg Eric L.
Publication year - 2015
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.7432
Subject(s) - chemistry , hydrogenase , fractionation , chromatography , organic chemistry , catalysis
Rationale Hydrogenases catalyze the reversible formation of H 2 from electrons and protons with high efficiency. Understanding the relationships between H 2 production, H 2 uptake, and H 2 ‐H 2 O exchange can provide insight into the metabolism of microbial communities in which H 2 is an essential component in energy cycling. Methods We used stable H isotopes ( 1 H and 2 H) to probe the isotope effects associated with three [FeFe]‐hydrogenases and three [NiFe]‐hydrogenases. Results All six hydrogenases displayed fractionation factors for H 2 formation that were significantly less than 1, producing H 2 that was severely depleted in 2 H relative to the substrate, water. Consistent with differences in their active site structure, the fractionation factors for each class appear to cluster, with the three [NiFe]‐hydrogenases (α = 0.27–0.40) generally having smaller values than the three [FeFe]‐hydrogenases (α = 0.41–0.55). We also obtained isotopic fractionation factors associated with H 2 uptake and H 2 ‐H 2 O exchange under conditions similar to those utilized for H 2 production, providing a more complete picture of the reactions catalyzed by hydrogenases. Conclusions The fractionation factors determined in our studies can be used as signatures for different hydrogenases to probe their activity under different growth conditions and to ascertain which hydrogenases are most responsible for H 2 production and/or uptake in complex microbial communities. Copyright © 2015 John Wiley & Sons, Ltd.