title: On the relationship between affinity for molecular hydrogen and the physiological directionality of hydrogenases.
abstract: The physiological significance of the generic reaction H(2)<-->2[H] is not always clear because hydrogenases may function in the breakdown of molecular hydrogen or in its synthesis or in both directions. Fe-hydrogenases have nevertheless been most often associated with proton reduction and NiFe-hydrogenases with hydrogen oxidation. A re-determination of the K(M) of H(2) oxidation by Pyrococcus furiosus NiFe-hydrogenase-I and by Desulfovibrio vulgaris Fe-hydrogenase suggests that affinity for hydrogen has been seriously underestimated and that the kinetics of hydrogen activation in relation to the directionality of hydrogenases should be re-evaluated.
authors.affiliation: Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands.
authors.forename: D J
authors.initials: DJ
authors.lastname: van Haaster
authors.forename: P-L
authors.initials: PL
authors.lastname: Hagedoorn
authors.forename: J A
authors.initials: JA
authors.lastname: Jongejan
authors.forename: W R
authors.initials: WR
authors.lastname: Hagen
mesh_terms: D006859:Hydrogen / Q000378:metabolism*; D006864:Hydrogenase / Q000378:metabolism*; D007700:Kinetics; D010084:Oxidation-Reduction
chemical_list: D006859:Hydrogen; C043296:nickel-iron hydrogenase; D006864:Hydrogenase