Figure 3. Comparative analysis of hydrogen-uptake hydrogenases in different E. coli K-12 derivatives.

A. Aliquots of crude extracts (25 µg protein) derived from the bacterial strains shown were separated by non-denaturing PAGE (7.5% w/v polyacrylamide) and subsequently stained for hydrogenase enzyme activity. The locations of hydrogenase 1 and hydrogenase 2 activity bands are shown. B. Western blot analysis of the unprocessed and processed forms of the HybC large subunit of hydrogenase 2 was performed using crude extracts (25 µg protein) derived from the bacterial strains indicated. Strain DHP-F2 is a derivative of MC4100 carrying a deletion in the hypF gene.