Haem-containing protein complexes of Acinetobacter calcoaceticus as secondary electron acceptors for quinoprotein glucose dehydrogenase

Two complete different quinoprotein glucose dehydrogenases (GDH) have been isolated from A. calcoaceticus LMD 79.41. One is a membrane-bound GDH (m-GDH), related to the GDH's in Escherichia coli and Pseudomonas species. The second is a soluble GDH (s-GDH) located in the periplasm and closely associated with the soluble cytochrome b-562, which is able to accept electrons from s-GDH. The physiological role of s-GDH is still unknown as it is unable to oxidize glucose in vivo. Here the authors report the (partial) purification and characterization of the membrane-bound b-type cytochrome complexes of A. calcoaceticus LMD 79.41.