The properties of hydrogenase from Thiocapsa roseopersicina

The soluble and chromatophore-bound hydrogenases from the purple sulphur bacterium Thiocapsa roseopersicina strain BBS were purified up to homogeneity and the properties studied. The amino acid composition of hydrogenase preparations from different fractions of T. roseopersicina is identical, glycine and alanine as N-terminal amino acid residues. In comparison with other hydrogenases, especially in the immobilized state, the preparations obtained are shown to be more stable to O2 during storage and they are characterized by high thermal stability. Inactivation is observed above 78--80 degrees C and the optimal temperature for enzyme action is 70 degrees C. The homogeneous enzyme preparations catalyse the exchange reaction between 2H2 and H2O and reversible redox reactions of methyl viologen and benzyl viologen as well as H2 formation from reduced ferredoxin. According to our data, the hydrogenase of T. roseopersicina bound with chromatophores is identical to the soluble one.