Quinoprotein D-glucose dehydrogenase of the Acinetobacter calcoaceticus respiratory chain: membrane-bound and soluble forms are different molecular species

Abstract

Acinetobacter calcoaceticus is known to contain soluble and membrane-bound quinoprotein D-glucose dehydrogenases, while other oxidative bacteria contain the membrane-bound enzyme exclusively. The two forms of glucose dehydrogenase were believed to be the same enzyme or interconvertible forms. Previously, Matsushita et al. [(1988) FEMS Microbiol. Lett 55, 53-58] showed that the two enzymes are different with respect to enzymatic and immunological properties, as well as molecular weight. In the present study, we purified both enzymes and compared their kinetics, reactivity with ubiquinone homologues, and immunological properties in detail. The purified membrane-bound enzyme had a molecular weight of 83,000, while the soluble form was 55,000. The purified enzymes exhibited totally different enzymatic properties, particularly with respect to reactivity toward ubiquinone homologues. The soluble enzyme reacted with short-chain homologues only, whereas the membrane-bound enzyme reacted with long-chain homologues including ubiquinone 9, the native ubiquinone of the A. calcoaceticus. Furthermore, the two enzymes were distinguished immunochemically; the membrane-bound enzyme did not cross-react with antibody raised against the soluble enzyme, nor did the soluble enzyme cross-react with antibody against the membrane-bound enzyme. Thus, each glucose dehydrogenase is a molecularly distinct entity, and the membrane-bound enzyme only is coupled to the respiratory chain via ubiquinone.

Serratia marcescens Quinoprotein Glucose Dehydrogenase Activity Mediates Medium Acidification and Inhibition of Prodigiosin Production by Glucose

“…It may be energetically beneficial for the bacteria to inhibit prodigiosin production in glucose-rich environments. This is based upon the observations that quinoprotein GDH activity leads to the establishment of a proton gradient that can be used for the uptake of amino acids and other molecules (1,32,33) whereas prodigiosin promotes H ϩ /Cl Ϫ symport across membranes (21,41,44), possibly uncoupling the proton gradient established through glucose oxidation. Consistent with this notion, Haddix and colleagues recently presented data suggesting that S. marcescens utilizes prodigiosin to reduce ATP production as a way to limit generation of damaging reactive oxygen species during stationary phase (21).…”

“…Glucose dehydrogenase was measured using a chromogenic reaction based on the method of Matsushita et al (33) but modified for use with 96-well plates. Bacteria were grown in 5-ml cultures of LB or LBG for 18 to 20 h. Aliquots (0.5 ml) were removed, and cells were pelleted.…”

Mutant Isolation of the Escherichia coli Quinoprotein Glucose Dehydrogenase and Analysis of Crucial Residues Asp-730 and His-775 for Its Function

“…Previous reports have indicated that GDH possesses the binding sites for PQQ (3,4), metal ions such as Mg 2ϩ or Ca 2ϩ (5,6), and ubiquinone (1,8,9) as well as substrate glucose. The enzyme from E. coli occurs as the apoenzyme (5) because the organism is unable to produce PQQ (6), but is readily reconstituted by incubation with PQQ and the metal ions (7).…”

Flexible and transparent biological electric power sources based on nanostructured electrodes

“…The enzyme oxidises a broad range of carbohydrates to the corresponding lactones, with concomitant reduction of PQQ to PQQH 2 and it is able to donate electrons to various artificial electron acceptors ( Figure 6) (Matsushita et al, 1989;. In paper III, PQQ-GDh was used as anodic enzyme for glucose oxidation and DET was achieved between the enzyme and the surface of the electrode, corroborating previous reports Razumiene et al, 2006;Zayats et al, 2005).…”