β Scribed by Steve W. Ragsdale; Lars G. Ljungdahl
No coin nor oath required. For personal study only.
Hydrogenase from fructose-grown cells of Acetobacterium woodii has been purified 70-fold to a specific activity of 3,500 gmol hydrogen oxidized per rain per mg of protein measured at 35~ and pH 7.6 with methyl viologen as electron acceptor. At the same conditions with reduced methyl viologen as electron donor the enzyme catalyzes the evolvement of 440 ~tmol of H2 per rain per mg of protein.
The enzyme was found in the soluble portion of the cell, indicating that it is either not membrane-bound or is loosely associated with the membrane. The purified enzyme, which does not contain nickel, exhibits spectroscopic properties similar to the iron-sulfur hydrogenase of Clostridium pasteurianum. The enzyme is strongly inhibited by carbon monoxide, with 50% inhibition occurring at approximately 7 nM CO. Ferredoxin, flavodoxin, and carbon monoxide dehydrogenase are reduced in hydrogen-dependent reaction by the A. woodi hydrogenase.
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