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Characterization of enzymes involved in the central metabolism of Gluconobacter oxydans.
Appl Microbiol Biotechnol. 2010 Oct; 88(3):711-8.AM

Abstract

Gluconobacter oxydans is an industrially important bacterium that lacks a complete Embden-Meyerhof pathway (glycolysis). The organism instead uses the pentose phosphate pathway to oxidize sugars and their phosphorylated intermediates. However, the lack of glycolysis limits the amount of NADH as electron donor for electron transport phosphorylation. It has been suggested that the pentose phosphate pathway contributes to NADH production. Six enzymes predicted to play central roles in intracellular glucose and gluconate flux were heterologously overproduced in Escherichia coli and characterized to investigate the intracellular flow of glucose and gluconates into the pentose phosphate pathway and to explore the contribution of the pentose phosphate pathway to NADH generation. The key pentose phosphate enzymes glucose 6-phosphate dehydrogenase (Gox0145) and 6-phosphogluconate dehydrogenase (Gox1705) had dual cofactor specificities but were physiologically NADP- and NAD-dependent, respectively. Putative glucose dehydrogenase (Gox2015) was NADP-dependent and exhibited a preference for mannose over glucose, whereas a 2-ketogluconate reductase (Gox0417) displayed dual cofactor specificity for NAD(P)H. Furthermore, a putative gluconokinase and a putative glucokinase were identified. The gluconokinase displayed high activities with gluconate and is thought to shuttle intracellular gluconate into the pentose phosphate pathway. A model for the trafficking of glucose and gluconates into the pentose phosphate pathway and its role in NADH generation is presented. The role of NADPH in chemiosmotic energy conservation is also discussed.

Authors+Show Affiliations

Institute fur Mikrobiologie und Biotechnologie, Universitat Bonn, 168 Meckenheimer Allee, 53515 Bonn, Germany.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

20676631

Citation

Rauch, Bernadette, et al. "Characterization of Enzymes Involved in the Central Metabolism of Gluconobacter Oxydans." Applied Microbiology and Biotechnology, vol. 88, no. 3, 2010, pp. 711-8.
Rauch B, Pahlke J, Schweiger P, et al. Characterization of enzymes involved in the central metabolism of Gluconobacter oxydans. Appl Microbiol Biotechnol. 2010;88(3):711-8.
Rauch, B., Pahlke, J., Schweiger, P., & Deppenmeier, U. (2010). Characterization of enzymes involved in the central metabolism of Gluconobacter oxydans. Applied Microbiology and Biotechnology, 88(3), 711-8. https://doi.org/10.1007/s00253-010-2779-9
Rauch B, et al. Characterization of Enzymes Involved in the Central Metabolism of Gluconobacter Oxydans. Appl Microbiol Biotechnol. 2010;88(3):711-8. PubMed PMID: 20676631.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Characterization of enzymes involved in the central metabolism of Gluconobacter oxydans. AU - Rauch,Bernadette, AU - Pahlke,Jennifer, AU - Schweiger,Paul, AU - Deppenmeier,Uwe, Y1 - 2010/07/30/ PY - 2010/06/22/received PY - 2010/07/10/accepted PY - 2010/07/09/revised PY - 2010/8/3/entrez PY - 2010/8/3/pubmed PY - 2010/12/14/medline SP - 711 EP - 8 JF - Applied microbiology and biotechnology JO - Appl. Microbiol. Biotechnol. VL - 88 IS - 3 N2 - Gluconobacter oxydans is an industrially important bacterium that lacks a complete Embden-Meyerhof pathway (glycolysis). The organism instead uses the pentose phosphate pathway to oxidize sugars and their phosphorylated intermediates. However, the lack of glycolysis limits the amount of NADH as electron donor for electron transport phosphorylation. It has been suggested that the pentose phosphate pathway contributes to NADH production. Six enzymes predicted to play central roles in intracellular glucose and gluconate flux were heterologously overproduced in Escherichia coli and characterized to investigate the intracellular flow of glucose and gluconates into the pentose phosphate pathway and to explore the contribution of the pentose phosphate pathway to NADH generation. The key pentose phosphate enzymes glucose 6-phosphate dehydrogenase (Gox0145) and 6-phosphogluconate dehydrogenase (Gox1705) had dual cofactor specificities but were physiologically NADP- and NAD-dependent, respectively. Putative glucose dehydrogenase (Gox2015) was NADP-dependent and exhibited a preference for mannose over glucose, whereas a 2-ketogluconate reductase (Gox0417) displayed dual cofactor specificity for NAD(P)H. Furthermore, a putative gluconokinase and a putative glucokinase were identified. The gluconokinase displayed high activities with gluconate and is thought to shuttle intracellular gluconate into the pentose phosphate pathway. A model for the trafficking of glucose and gluconates into the pentose phosphate pathway and its role in NADH generation is presented. The role of NADPH in chemiosmotic energy conservation is also discussed. SN - 1432-0614 UR - https://www.unboundmedicine.com/medline/citation/20676631/Characterization_of_enzymes_involved_in_the_central_metabolism_of_Gluconobacter_oxydans_ L2 - https://dx.doi.org/10.1007/s00253-010-2779-9 DB - PRIME DP - Unbound Medicine ER -