GLUCOSE-DEHYDROGENASE FROM THE HALOPHILIC ARCHAEON HALOFERAX-MEDITERRANEI - ENZYME-PURIFICATION, CHARACTERIZATION AND N-TERMINAL SEQUENCE

An NAD(P)-glucose dehydrogenase from the extremely halophilic Archaeon , Haloferax mediterranei, has been purified to electrophoretic homogen eity, The purified enzyme has been characterised with respect to its c ofactor specificity, subunit composition and its salt and thermal stab ility, The N-terminal amino acid sequence has been determined and N-te rminus alignment with sequences of other glucose dehydrogenases shows that the halophilic enzyme most closely resembles the NAD(P)-linked gl ucose dehydrogenase from the thermophilic Archaeon Thermoplasma acidop hilum. However, the halophilic glucose dehydrogenase appears to be a d imeric protein, in contrast to the tetrameric enzyme from the thermoph ile.