title: Immobilization of the [FeFe]-hydrogenase CrHydA1 on a gold electrode: design of a catalytic surface for the production of molecular hydrogen.
abstract: Hydrogenase-modified electrodes are a promising catalytic surface for the electrolysis of water with an overpotential close to zero. The [FeFe]-hydrogenase CrHydA1 from the photosynthetic green alga Chlamydomonas reinhardtii is the smallest [FeFe]-hydrogenase known and exhibits an extraordinary high hydrogen evolution activity. For the first time, we immobilized CrHydA1 on a gold surface which was modified by different carboxy-terminated self-assembled monolayers. The immobilization was in situ monitored by surface-enhanced infrared spectroscopy. In the presence of the electron mediator methyl viologen the electron transfer from the electrode to the hydrogenase was detected by cyclic voltammetry. The hydrogen evolution potential (-290 mV vs NHE, pH 6.8) of this protein modified electrode is close to the value for bare platinum (-270 mV vs NHE). The surface coverage by CrHydA1 was determined to 2.25 ng mm(-2) by surface plasmon resonance, which is consistent with the formation of a protein monolayer. Hydrogen evolution was quantified by gas chromatography and the specific hydrogen evolution activity of surface-bound CrHydA1 was calculated to 1.3 micromol H(2)min(-1)mg(-1) (or 85 mol H(2)min(-1)mol(-1)). In conclusion, a viable hydrogen-evolving surface was developed that may be employed in combination with immobilized photosystems to provide a platform for hydrogen production from water and solar energy with enzymes as catalysts.
authors.affiliation: Bielefeld University, Department of Chemistry, D-33615 Bielefeld, Germany.
authors.forename: Henning
authors.initials: H
authors.lastname: Krassen
authors.forename: Sven
authors.initials: S
authors.lastname: Stripp
authors.forename: Gregory
authors.initials: G
authors.lastname: von Abendroth
authors.forename: Kenichi
authors.initials: K
authors.lastname: Ataka
authors.forename: Thomas
authors.initials: T
authors.lastname: Happe
authors.forename: Joachim
authors.initials: J
authors.lastname: Heberle
mesh_terms: D000327:Adsorption; D000818:Animals; D019149:Bioreactors; D016825:Chlamydomonas reinhardtii / Q000201:enzymology; D046969:Clostridium acetobutylicum / Q000235:genetics; D004566:Electrodes; D004800:Enzymes, Immobilized / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D006046:Gold / Q000737:chemistry*; D006859:Hydrogen / Q000378:metabolism*; D006864:Hydrogenase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D007506:Iron-Sulfur Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D007700:Kinetics; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D017550:Spectroscopy, Fourier Transform Infrared; D020349:Surface Plasmon Resonance; D013499:Surface Properties
chemical_list: D004800:Enzymes, Immobilized; D007506:Iron-Sulfur Proteins; D011994:Recombinant Proteins; D006046:Gold; D006859:Hydrogen; C118830:iron hydrogenase; D006864:Hydrogenase