Differential induction of enzymes involved in anaerobic metabolism of aromatic compounds in the denitrifying bacterium Thauera aromatica |
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Authors: | J Heider Matthias Boll Klaus Breese Sabine Breinig Christa Ebenau-Jehle Ulrich Feil Nasser Gad’on Diana Laempe Birgitta Leuthner M El-Said Mohamed Sabine Schneider Gerhard Burchhardt Georg Fuchs |
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Institution: | Institut für Biologie II, Universit?t Freiburg, Sch?nzlestrasse 1, D-79?104 Freiburg, Germany e-mail heiderj@ruf.uni-freiburg.de Tel. +49-761-203-2774; Fax +49-761-203-2626, DE Institut für Genetik und Biochemie, Universit?t Greifswald, D-17?487 Greifswald, Germany, DE
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Abstract: | Differential induction of enzymes involved in anaerobic metabolism of aromatic substrates was studied in the denitrifying
bacterium Thauera aromatica. This metabolism is divided into (1) peripheral reactions transforming the aromatic growth substrates to the common intermediate
benzoyl-CoA, (2) the central benzoyl-CoA pathway comprising ring-reduction of benzoyl-CoA and subsequent β-oxidation to 3-hydroxypimelyl-CoA,
and (3) the pathway of β-oxidation of 3-hydroxypimelyl-CoA to three acetyl-CoA and CO2. Regulation was studied by three methods.
1. Determination of protein patterns of cells grown on different substrates. This revealed several strongly substrate-induced
polypeptides that were missing in cells grown on benzoate or other intermediates of the respective metabolic pathways.
2. Measurement of activities of known enzymes involved in this metabolism in cells grown on different substrates. The enzyme
pattern found is consistent with the regulatory pattern deduced from simultaneous adaptation of cells to utilisation of other
aromatic substrates.
3. Immunological detection of catabolic enzymes in cells grown on different substrates. Benzoate-CoA ligase and 4-hydroxybenzoate-CoA
ligase were detected only in cells yielding the respective enzyme activity. However, presence of the subunits of benzoyl-CoA
reductase and 4-hydroxybenzoyl-CoA reductase was also recorded in some cell batches lacking enzyme activity. This possibly
indicates an additional level of regulation on protein level for these two reductases.
Received: 22 December 1997 / Accepted: 12 May 1998 |
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Keywords: | Anaerobic aromatic metabolism Benzoyl-CoA reductase Phenylphosphate carboxylase 4-Hydroxybenzoyl-CoA reductase 2-Aminobenzoate Phenylalanine Phenylacetyl-CoA Phenylglyoxylate Toluene CoA ligase |
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