PURIFICATION AND CHARACTERIZATION OF MEMBRANE-BOUND HYDROGENASE FROM A THERMOPHILIC HYDROGEN-OXIDIZING BACTERIUM, PSEUDOMONAS-HYDROGENOTHERMOPHILA STRAIN TH-1

A membrane-bound hydrogenase was purified aerobically by one step usin g a hydroxyapatite column after solubilization by acetone treatment fr om a thermophilic hydrogen-oxidizing bacterium, Pseudomonas hydrogenot hermophila strain TH-1, The enzyme consists of two polypeptides of 63 and 31 kDa, respectively. The amino-terminal amino acid sequences of b oth subunits were homologous to membrane-bound type [Ni-Fe] hydrogenas es from other origins, The thermostability under a hydrogen gas atmosp here is highly stable at 50 degrees C, which is the optimum temperatur e for the cell growth.