An electrochemical and microbiological study of the formic acid-formic dehydrogenlyase system

Initial rates of hydrogen evolution from the formic acid-formic dehydrogenlyase system were determined as a function of enzyme and substrate concentration, using a resting cell preparation of E. coli. The decrease of rate of hydrogen production with time (to about one third of its initial value in 6 hr) was shown to be due to a decrease in specific activity of the enzyme rather than a change in substrate concentration.

The hydrogen produced by the splitting of the formic acid molecules can be oxidized anodically in situ on bright or platinized Pt electrode, without poisoning of the electrode surface. Direct charge transfer from the enzyme-substrate complex to the electrode could not be detected.