Fermentation enzymes in strains of Paracoccus denitrificans

Nokhal, T. H.; Schlegel, H. G.

doi:10.1007/bf00446780

Cited by 4 publications

(3 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The excretion of succinate and fumarate by cells growing photosynthetically on malate has been detected using I H-NMR (D.J. Richardson [138][139][140]. In A. eutrophus, the excretion of metabolites was greater in a PHB-mutant than in the wild-type [138].…”

Section: H 2 Photoproduction and The Excretion Of Carbon Compoundsmentioning

confidence: 99%

Biochemical genetics revisited: the use of mutants to study carbon and nitrogen metabolism in the photosynthetic bacteria

Willison¹

1993

FEMS Microbiology Letters

View full text Add to dashboard Cite

The biochemical genetics approach is defined as the use of mutants, in comparative studies with the wild‐type, to obtain information about biochemical and physiological processes in complex metabolic systems. This approach has been used extensively, for example in studies on the bioenergetics of the photosynthetic bacteria, but has been applied less frequently to studies of intermediary carbon and nitrogen metabolism in phototrophic organisms. Several important processes in photosynthetic bacteria—the regulation of nitrogenase synthesis and activity, the control of intracellular redox balance during photoheterotrophic growth, and chemotaxis—have been shown to involve metabolism. However, current understanding of carbon and nitrogen metabolism in these organisms is insufficient to allow a complete understanding of these phenomena. The purpose of the present review is to give an overview of carbon and nitrogen metabolism in the photosynthetic bacteria, with particular emphasis on work carried out with mutants, and to indicate areas in which the biochemical genetics approach could be applied successfully. In particular, it will be argued that, in the case of Rhodobacter capsulatus and Rb. sphaeroides, two species which are fast‐growing, possess a versatile metabolism, and have been extensively studied genetically, it should be possible to obtain a complete, integrated description of carbon and nitrogen metabolism, and to undertake a qualitative and quantitative analysis of the flow of carbon and reducing equivalents during photoheterotrophic growth. This would require a systematic biochemical genetic study employing techniques such as HPLC, NMR, and mass spectrometry, which are briefly discussed. The review is concerned mainly with Rb. capsulatus and Rb. sphaeroides, since most studies with mutants have been carried out with these organisms. However, where possible, a comparison is made with other species of purple non‐sulphur bacteria and with purple and green sulphur bacteria, and recent literature relevant to these organisms has been cited.

show abstract

Section: H 2 Photoproduction and The Excretion Of Carbon Compoundsmentioning

confidence: 99%

Biochemical genetics revisited: the use of mutants to study carbon and nitrogen metabolism in the photosynthetic bacteria

Willison¹

1993

FEMS Microbiology Letters

View full text Add to dashboard Cite

show abstract

“…In malate incubated cells, glycogen decreased by ~40% in the presence of K + and glucose increased by ~1 mM, an amount equivalent to ~80% of the hydrolyzed glycogen (S2 Fig) . Thus, even in the absence of external glucose, a general activation of glucose utilization by K + was evident by an increased glucose availability and an activation of glycolytic enzymes. Surprisingly, lactate concentrations under all conditions was very high (6-7 mM) even though P. denitrificans cells lack the NAD-dependent lactate dehydrogenase linked to glycolysis [39]. The lactate concentrations reported from the metabolomic analysis were confirmed by two other independent methods: short-chain fatty acid reverse chromatography [40] and by HPLC-mass spectrometry [41].…”

Section: Changes In Concentrations Of Metabolites In the Presence Of K +mentioning

confidence: 67%

“…Surprisingly, lactate concentrations under all conditions was very high (6–7 mM) even though P . denitrificans cells lack the NAD-dependent lactate dehydrogenase linked to glycolysis [ 39 ]. The lactate concentrations reported from the metabolomic analysis were confirmed by two other independent methods: short-chain fatty acid reverse chromatography [ 40 ] and by HPLC-mass spectrometry [ 41 ].…”

Section: Resultsmentioning

confidence: 99%

Energy homeostasis is a conserved process: Evidence from Paracoccus denitrificans’ response to acute changes in energy demand

Covián

Edwards

et al. 2021

PLoS ONE

View full text Add to dashboard Cite

Paracoccus denitrificans is a model organism for the study of oxidative phosphorylation. We demonstrate a very high respiratory capacity compared to mitochondria when normalizing to cytochrome aa3 content even in the absence of alternative terminal oxidases. To gain insight into conserved mechanisms of energy homeostasis, we characterized the metabolic response to K+ reintroduction. A rapid 3-4-fold increase in respiration occurred before substantial cellular K+ accumulation followed by a sustained increase of up to 6-fold that persisted after net K+ uptake stopped. Proton motive force (Δp) was slightly higher upon addition of K+ with ΔpH increasing and compensating for membrane potential (ΔΨ) depolarization. Blocking the F0F1-ATP synthase (Complex V) with venturicidin revealed that the initial K+-dependent respiratory activation was primarily due to K+ influx. However, the ability to sustain an increased respiration rate was partially dependent on Complex V activity. The 6-fold stimulation of respiration by K+ resulted in a small net reduction of most cytochromes, different from the pattern observed with chemical uncoupling and consistent with balanced input and utilization of reducing equivalents. Metabolomics showed increases in glycolytic and TCA cycle intermediates together with a decrease in basic amino acids, suggesting an increased nitrogen mobilization upon K+ replenishment. ATP and GTP concentrations increased after K+ addition, indicating a net increase in cellular potential energy. Thus, K+ stimulates energy generation and utilization resulting in an almost constant Δp and increased high-energy phosphates during large acute and steady state changes in respiration. The specific energy consuming processes and signaling events associated with this simultaneous activation of work and metabolism in P. denitrificans remain unknown. Nevertheless, this homeostatic behavior is very similar to that observed in mitochondria in tissues when cellular energy requirements increase. We conclude that the regulation of energy generation and utilization to maintain homeostasis is conserved across the prokaryote/eukaryote boundary.

show abstract

(R,R)-Butanediol dehydrogenase

Schomburg¹,

Stephan²

1995

Enzyme Handbook 9

View full text Add to dashboard Cite

Fermentation enzymes in strains of Paracoccus denitrificans

Cited by 4 publications

References 13 publications

Biochemical genetics revisited: the use of mutants to study carbon and nitrogen metabolism in the photosynthetic bacteria

Biochemical genetics revisited: the use of mutants to study carbon and nitrogen metabolism in the photosynthetic bacteria

Energy homeostasis is a conserved process: Evidence from Paracoccus denitrificans’ response to acute changes in energy demand

(R,R)-Butanediol dehydrogenase

Contact Info

Product

Resources

About