Cloning of the genes encoding the two different glucose dehydrogenases from Acinetobacter calcoaceticus.

Glucose dehydrogenase (GDH) is a PQQ dependent bacterial enzyme which converts aldoses to their corresponding acids. A. calcoaceticus contains two different PQQ dependent glucose dehydrogenases designated GDH-A which is active in vivo and GDH-B of which only in vitro activity can be shown. We cloned the genes coding for the two GDH enzymes. The DNA sequences of both gdh genes were determined. There is no obvious homology between gdhA and gdhB. Both GDH enzymes oxidize D-glucose in vitro but disaccharides are specific GDH-B substrates and 2-deoxyglucose is specifically oxidized by GDH-A.