Continuous monitoring of the activation and activity of [NiFe]-hydrogenases by membrane-inlet mass spectrometry

摘要

The hydrogen-deuterium (H~+/D_2) exchange reaction catalyzed by [NiFe]-hydrogenases in the D_2/H_2O system has been used to study enzyme activation and activity by membrane-inlet mass spectrometry. The activation of the [NiFe]-hydrogenases from Thiocapsa roseopersicina (HynSL), Desulfovibrio fructosovorans (HynSL), Desulfomicrobium baculatum (HysSL), Rhodobacter capsulatus (HupUV), and of the bidirectional tetrameric HoxFUYH enzymes from Synechocystis PCC 6308 (Gloeocapsa alpicola) and Anabaena variabilis ATCC 29413 was determined in response to oxygen depletion and to re-ductant addition (molecular hydrogen, reduced methyl viologen). Natural physiological activators (NADH, NADPH) of the bidirectional [NiFe] hydrogenases could also be identified by the H~+/D_2 exchange reaction. The data are discussed in the light of current models of hydrogenase catalytic mechanism.