| Autor: |
Leutwein, Christina, Heider, Johann |
| Předmět: |
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| Zdroj: |
Archives of Microbiology; Dec2002, Vol. 178 Issue 6, p517-524, 8p |
| Abstrakt: |
The first intermediate of anaerobic toluene catabolism, (R)-benzylsuccinate, is formed by enzymic addition of the methyl group of toluene to a fumarate cosubstrate and is subsequently activated to (R)-2-benzylsuccinyl-CoA. This compound is then oxidised to benzoyl-CoA and succinyl-CoA by a specific β-oxidation pathway. The enzyme catalysing the first oxidation step of this pathway, (R)-benzylsuccinyl-CoA dehydrogenase, is encoded by the bbsG gene in Thauera aromatica. It was functionally overproduced in Escherichia coli, purified and characterised. The enzyme is a homotetramer with a subunit size of 45 kDa and contains one FAD per subunit. It is highly specific for (R)-benzylsuccinyl-CoA and is inhibited by (S)-benzylsuccinyl-CoA. An apparent Km value of 110±10 µM was obtained for (R)-benzylsuccinyl-CoA. The reaction product of (R)-benzylsuccinyl-CoA dehydrogenase was identified as (E)-benzylidene-succinyl-CoA by comparison with the chemically synthesised compound, which was obtained via a new synthetic procedure. (R)-Benzylsuccinyl-CoA dehydrogenase was detected as a specifically substrate-induced protein in toluene- and m-xylene-grown cells of several bacterial species, using enzyme activity and immunological detection. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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