| Autor: |
Schöcke, Ludger, Schink, Bernhard |
| Zdroj: |
Archives of Microbiology; Apr1999, Vol. 171 Issue 5, p331-337, 7p |
| Abstrakt: |
The pathway of fermentative benzoate degradation by the syntrophically fermenting bacterium Syntrophus gentianae was studied by measurement of enzyme activities in cell-free extracts. Benzoate was activated by a benzoate-CoA ligase reaction, forming AMP and pyrophosphate, which was subsequently cleaved by a membrane-bound proton-translocating pyrophosphatase. Glutaconyl-CoA (formed from hypothetical pimelyl-CoA and glutaryl-CoA intermediates) was decarboxylated to crotonyl-CoA by a sodium-ion-dependent membrane-bound glutaconyl-CoA decarboxylase, a biotin enzyme that could be inhibited by avidin. The overall energy budget of this fermentation could be balanced only if the dearomatizing reduction of benzoyl-CoA is assumed to produce cyclohexene carboxyl-CoA rather than cyclohexadiene carboxyl-CoA, although experimental evidence of this reaction is still insufficient. With this assumption, benzoate degradation by S. gentianae can be balanced to yield one-third to two-thirds of an ATP unit per benzoate degraded, in accordance with earlier measurements of whole-cell energetics. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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