Investigating and exploiting the electrocatalytic properties of hydrogenases.

A variety of dynamic electrochemical techniques are being applied in order to learn about the properties of hydrogenases. The H2 production and oxidation in microbes are catalyzed at iron or nickel and iron catalytic centers contained in highly active enzymes called hydrogenases. The hydrogenases becomes electroactive at electrode when attached to the electrode surface. The application of protein film voltammetry (PFV) controls and measures catalytic electron flow simultaneously and link catalytic activity to different components and properties of the enzyme. It also allows exploration of properties and can both complement and "trailblaze" spectroscopic ad structural investigations. The pyrolytic graphite "edge" surface (PGE) electrode has been proven to be an excellent conducting substrate for direct absorptions of proteins and highly electroactive films of a number of [NiFe]- and [FeFe]-hydrogenases. The high activity of hydrogenases, high affinity for H2 and high selectivity for H2 over other small molecules have been exploited in small-scale fuel cells producing electricity from H2 at low levels in air or with high levels of contaminating CO