Preliminary purification of an iron hydrogenase from marine green alga Platymonas subcordiformis

Green algae are the only eukaryotic organisms for which hydrogenase activity has been well documented (Ueno et al., 1999). In this study, hydrogenase from a marine green alga Platymonas subcordiformis (Guan et al., 2004), was purified through three steps under strict anaerobic conditions: ammonium sulfate precipitation, DEAE-52, and Sephadex G-100. Further investigations demonstrated that this partially purified hydrogenase showed a highest in vitro activity of 148 nmol H2 h−1 g Chl−1, at the optimum temperature of 45 ◦C and pH value of 7.5, using reduced methyl viologen as an electron donor. The specific activity of crude extractwas 0.14 U/mg protein, after disrupting algal cells with glass beads at 4 ◦C (Yan et al., 2008). A yield of 85% as judged by the activity was obtained by 50–80% ammonium sulfate precipitation. After ion-exchange chromatography and gel filtration chromatography, two bands with molecular masses of 43 and 32 kDa were revealed on SDS-PAGE, and the former was proved to be hydrogenase. Further study on the amino acid sequences of the hydrogenase is currently under way