Enzymes of anaerobic metabolism of phenolic compounds

Biegert, Thomas; Altenschmidt, Uwe; Eckerskorn, Christoph; Fuchs, Georg

doi:10.1111/j.1432-1033.1993.tb17794.x

Cited by 72 publications

(49 citation statements)

References 35 publications

(24 reference statements)

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“…Little is known so far about anaerobic degradation of 3-hydroxybenzoate. Although for this isomer, CoA-thioesterification (Heising et al 1991;Biegert et al 1993) and reductive dehydroxylation (Tschech and Schink 1986;Brackmann and Fuchs 1993) were assumed to be the first steps in anaerobic degradation, detailed studies on this pathway are still necessary.…”

Section: Introductionmentioning

confidence: 99%

Initial steps in the fermentation of 3-hydroxybenzoate by Sporotomaculum hydroxybenzoicum

Müller

Schink

2000

Archives of Microbiology

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The anaerobic bacterium Sporotomaculum hydroxybenzoicum ferments 3-hydroxybenzoate to acetate, butyrate, and CO 2 . 3-Hydroxybenzoate was activated to 3-hydroxybenzoyl-CoA in a CoA-transferase reaction with acetyl-CoA or butyryl-CoA as CoA donors. 3-Hydroxybenzoyl-CoA was reductively dehydroxylated, forming benzoyl-CoA. This reaction was measured in cell-free extracts with cob(I)alamin as low-potential electron donor. No evidence was obtained that cob(I)alamin is the physiological electron donor; however, inhibitor studies indicated involvement of a strong nucleophile in the reaction. Benzoate was degraded by dense cell suspensions without a lag phase until an in situ ∆G′ value <-25 kJ mol -1 was reached. Benzoyl-CoA reductase was not detected. Enzyme activities for all reaction steps from glutaryl-CoA to butyryl-CoA, and ATP formation via acetate kinase were detected in cell-free extracts. GlutaconylCoA decarboxylase is likely to act as a primary sodium ion pump.

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Section: Introductionmentioning

confidence: 99%

Initial steps in the fermentation of 3-hydroxybenzoate by Sporotomaculum hydroxybenzoicum

Müller

Schink

2000

Archives of Microbiology

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“…We have to date, however, been unable to develop an assay for this activity. Carboxylation of phenol results in the formation of 4-hydroxybenzoate (44) which is removed by an active CoA ligase (2,24), perhaps to shift the equilibrium to allow the energetically unfavourable carboxylation reaction to proceed. A similar mechanism does not appear to play a role in the anaerobic acetone metabolism of D. biacutus, since (i) apparently no free acid intermediate is formed, (ii) the intracellular acetoacetyl-CoA ester concentration is not low enough to result in a significant shift in the equilibrium of the initial reactions, (iii) this concentration is 10 13 times higher than that predicted for a carboxylation not coupled to an energy-utilizing step, and (iv) the kinetic properties and substrate affinities of the enzymes acting on the proposed initial product (acetoacetyl-CoA) would result in virtually no catabolic flux at acetoacetyl-CoA concentrations predicted by a carboxylation reaction without an energy-utilizing step.…”

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Catabolic and anabolic enzyme activities and energetics of acetone metabolism of the sulfate-reducing bacterium Desulfococcus biacutus

Janssen

Schnik

1995

J Bacteriol

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Acetone degradation by cell suspensions of Desulfococcus biacutus was CO 2 dependent, indicating initiation by a carboxylation reaction, while degradation of 3-hydroxybutyrate was not CO 2 dependent. Growth on 3-hydroxybutyrate resulted in acetate accumulation in the medium at a ratio of 1 mol of acetate per mol of substrate degraded. In acetone-grown cultures no coenzyme A (CoA) transferase or CoA ligase appeared to be involved in acetone metabolism, and no acetate accumulated in the medium, suggesting that the carboxylation of acetone and activation to acetoacetyl-CoA may occur without the formation of a free intermediate. Catabolism of 3-hydroxybutyrate occurred after activation by CoA transfer from acetyl-CoA, followed by oxidation to acetoacetyl-CoA. In both acetone-grown cells and 3-hydroxybutyrate-grown cells, acetoacetyl-CoA was thiolytically cleaved to two acetyl-CoA residues and further metabolized through the carbon monoxide dehydrogenase pathway. Comparison of the growth yields on acetone and 3-hydroxybutyrate suggested an additional energy requirement in the catabolism of acetone. This is postulated to be the carboxylation reaction (⌬G؇ for the carboxylation of acetone to acetoacetate, ؉17.1 kJ ⅐ mol ؊1). At the intracellular acyl-CoA concentrations measured, the net free energy change of acetone carboxylation and catabolism to two acetyl-CoA residues would be close to 0 kJ ⅐ mol of acetone ؊1, if one mol of ATP was invested. In the absence of an energy-utilizing step in this catabolic pathway, the predicted intracellular acetoacetyl-CoA concentration would be 10 13 times lower than that measured. Thus, acetone catabolism to two acetyl-CoA residues must be accompanied by the utilization of the energetic equivalent of (at least) one ATP molecule. Measurement of enzyme activities suggested that assimilation of acetyl-CoA occurred through a modified citric acid cycle in which isocitrate was cleaved to succinate and glyoxylate. Malate synthase, condensing glyoxylate and acetyl-CoA, acted as an anaplerotic enzyme. Carboxylation of pyruvate or phosphoenolpyruvate could not be detected.The anaerobic metabolism of acetone appears to involve an initial carboxylation of acetone to acetoacetate (or acetoacetyl coenzyme A [acetoacetyl-CoA]), followed by thiolytic cleavage to two acetyl-CoA residues (3, 32-35). The carboxylation reaction has not been measured in vitro, and evidence has come from 14 C labelling studies (32,33,35). Carboxylation reactions appear to play a role in a number of anaerobic transformations (16, 44), but these reactions have not been well studied. The carboxylation of acetone to acetoacetate, CH 3 COCH 3 ϩ HCO 3), is an endergonic reaction (42). Thus, the energetic equivalent of about 1/3 mol of ATP (⌬GЊЈ of ATP hydrolysis, Ϫ50 kJ ⅐ mol Ϫ1 [42]) is required, but the mechanism of coupling is not known. In addition, attempts to measure the carboxylase in sulfate-reducing bacteria have remained unsuccessful (21).Many genera of sulfate-reducing bacteria are able to oxidize completely (to CO ...

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“…Protein was quantified by the method of Bradford (7) (28). Purification of the antibodies on a protein A column (Pharmacia, Freiburg, Germany) and Western blots were performed as described previously (5).…”

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New aerobic benzoate oxidation pathway via benzoyl-coenzyme A and 3-hydroxybenzoyl-coenzyme A in a denitrifying Pseudomonas sp

et al. 1993

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A denitrifying Pseudomonas sp. is able to oxidize aromatic compounds compounds completely to CO2, both aerobically and anaerobically. It is shown that benzoate is aerobically oxidized by a new degradation pathway via benzoyl-coenzyme A (CoA) and 3-hydroxybenzoyl-CoA. The organism grew aerobically with benzoate, 3-hydroxybenzoate, and gentisate; catechol, 2-hydroxybenzoate, and protocatechuate were not used, and 4-hydroxybenzoate was a poor substrate. Mutants were obtained which were not able to utilize benzoate as the sole carbon source aerobically but still used 3-hydroxybenzoate or gentisate. Simultaneous adaptation experiments with whole cells seemingly suggested a sequential induction of enzymes of a benzoate oxidation pathway via 3-hydroxybenzoate and gentisate. Cells grown aerobically with benzoate contained a benzoate-CoA ligase (AMP forming) (0.1 mumol min-1 mg-1) which converted benzoate but not 3-hydroxybenzoate into its CoA thioester. The enzyme of 130 kDa composed of two identical subunits of 56 kDa was purified and characterized. Cells grown aerobically with 3-hydroxybenzoate contained a similarly active CoA ligase for 3-hydroxybenzoate, 3-hydroxybenzoate-CoA ligase (AMP forming). Extracts from cells grown aerobically with benzoate catalyzed a benzoyl-CoA- and flavin adenine dinucleotide-dependent oxidation of NADPH with a specific activity of at least 25 nmol NADPH oxidized min-1 mg of protein-1; NADH and benzoate were not used. This new enzyme, benzoyl-CoA 3-monooxygenase, was specifically induced during aerobic growth with benzoate and converted [U-14C]benzoyl-CoA stoichiometrically to [14C]3-hydroxybenzoyl-CoA.

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Enzymes of anaerobic metabolism of phenolic compounds

Cited by 72 publications

References 35 publications

Initial steps in the fermentation of 3-hydroxybenzoate by Sporotomaculum hydroxybenzoicum

Initial steps in the fermentation of 3-hydroxybenzoate by Sporotomaculum hydroxybenzoicum

Catabolic and anabolic enzyme activities and energetics of acetone metabolism of the sulfate-reducing bacterium Desulfococcus biacutus

New aerobic benzoate oxidation pathway via benzoyl-coenzyme A and 3-hydroxybenzoyl-coenzyme A in a denitrifying Pseudomonas sp

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