Isotopic fractionation associated with [NiFe]‐ and [FeFe]‐hydrogenases. (21st December 2015)

• Record Type: Journal Article
• Authors: Yang, Hui; Gandhi, Hasand; Cornish, Adam J.; Moran, James J.; Kreuzer, Helen W.; Ostrom, Nathaniel E.; Hegg, Eric L.
• Is Part Of: Rapid communications in mass spectrometry. Volume 30:Number 2(2016)
• Page Start: 285
• Page End: 292
• Publication Date: 2015-12-21
• Subjects: Mass spectrometry -- Periodicals; 543.65
• DOI: 10.1002/rcm.7432
• Languages: English
• ISSNs: 0951-4198

Abstract

Abstract : Rationale: Hydrogenases catalyze the reversible formation of H2 from electrons and protons with high efficiency. Understanding the relationships between H2 production, H2 uptake, and H2 ‐H2 O exchange can provide insight into the metabolism of microbial communities in which H2 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 H2 formation that were significantly less than 1, producing H2 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 H2 uptake and H2 ‐H2 O exchange under conditions similar to those utilized for H2 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 H2 production and/or uptake in complex microbial communities. Copyright © 2015 John Wiley & Sons, Ltd.