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![Protein Film Infrared Electrochemistry Demonstrated for Study of H2 Oxidation by a [NiFe] Hydrogenase](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F55858.jpg&w=3840&q=50)
Protein Film Infrared Electrochemistry Demonstrated for Study of H2 Oxidation by a [NiFe] Hydrogenase
Published on: December 4, 2017
Isocyanides inhibit [Fe]-hydrogenase with very high affinity
1Max-Planck-Institut für terrestrische Mikrobiologie, Marburg, Germany. shima@mpi-marburg.mpg.de
Abstract:
[Fe]-Hydrogenase catalyzes the reversible activation of H(2). CO and CN(-) inhibit this enzyme with low affinity (K(i)≅0.1 mM) by binding to the iron site of the bound iron-guanyrylpyridinol cofactor. We report here that isocyanides, which are formally isoelectronic with CO and CN(-), strongly inhibit [Fe]-hydrogenase (K(i) as low as 1 nM). The [NiFe]- and [FeFe]-hydrogenases tested were not inhibited by isocyanides. UV-Vis and infrared spectra revealed that the isocyanides bind to the iron center of [Fe]-hydrogenase. The inhibition kinetics are in agreement with the proposed catalytic mechanism, including the open/closed conformational change of the enzyme.
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