ISSN:
1432-072X
Keywords:
Aromatic compounds
;
Benzoic acid
;
2-Aminobenzoate
;
Anthranilic acid
;
Acyl CoA Synthetases
;
Monooxygenase
;
2-Aminobenzoyl CoA reductase
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract The initial reactions possibly involved in the acrobic and anaerobic metabolism of aromatic acids by a denitrifying Pseudomonas strain were studied. Several acyl CoA synthetases were found supporting the view that activation of several aromatic acids preceeds degradation. A benzoyl CoA synthetase activity (AMP forming) (apparent K m values of the enzyme from nitrate grown cells: 0.01 mM benzoate, 0.2 mM ATP, 0.2 mM coenzyme A) was present in aerobically grown and anaerobically, nitrate grown cells when benzoate or other aromatic acids were present. In addition to benzoate and fluorobenzoates, also 2-amino-benzoate was activated, albeit with unfavorable K m (0.5 mM 2-aminobenzoate). A 2-aminobenzoyl CoA synthetase (AMP forming) was induced both aerobically and anaerobically with 2-aminobenzoate as growth substrate which had a similar substrate spectrum but a low K m for 2-aminobenzoate (〈0.02 mM). Anaerobic growth on 4-hydroxybenzoate induced a 4-hydroxybenzoyl CoA synthetase, and cyclohexanecarboxylate induced another synthetase. In contrast, 3-hydroxybenzoate and phenyl-acetate grown anaerobic cells appeared not to activate the respective substrates at sufficient rates. Contrary to an earlier report extracts from aerobic and anaerobic 2-aminobenzoate grown cells catalysed a 2-aminobenzoyl CoA-dependent NADH oxidation. This activity was 10–20 times higher in aerobic cells and appeared to be induced by 2-aminobenzoate and oxygen. In vitro, 2-aminobenzoyl CoA reduction was dependent on 2-aminobenzoyl CoA NAD(P)H, and oxygen. A novel mechanism of aerobic 2-aminobenzoate degradation is suggested, which proceeds via 2-aminobenzoyl CoA.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00414434
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