Oxalate metabolism by the acetogenic bacterium Moorella thermoacetica.
Whole-cell and cell-extract experiments were performed to study the mechanism of oxalate metabolism in the acetogenic bacterium Moorella thermoacetica. In short-term, whole-cell assays, oxalate consumption was low unless cell suspensions were supplemented with CO(2), KNO(3), or Na(2)S(2)O(3). Cell extracts catalyzed the oxalate-dependent reduction of benzyl viologen. Oxalate consumption occurred concomitant to benzyl viologen reduction; when benzyl viologen was omitted, oxalate was not appreciably consumed. Based on benzyl viologen reduction, specific activities of extracts averaged 0.6 micromol oxalate oxidized min(-1) mg protein(-1). Extracts also catalyzed the formate-dependent reduction of NADP(+); however, oxalate-dependent reduction of NADP(+) was negligible. Oxalate- or formate-dependent reduction of NAD(+) was not observed. Addition of coenzyme A (CoA), acetyl-CoA, or succinyl-CoA to the assay had a minimal effect on the oxalate-dependent reduction of benzyl viologen. These results suggest that oxalate metabolism by M. thermoacetica requires a utilizable electron acceptor and that CoA-level intermediates are not involved.
Daniel
Steven L
SL
Department of Biological Sciences, Eastern Illinois University, Charleston, IL 61920, USA. cfsld@eiu.edu
Pilsl
Christine
C
Drake
Harold L
HL
D000085:Acetates / Q000378:metabolism; D004579:Electron Transport; D004734:Energy Metabolism; D006094:Gram-Positive Bacteria / Q000254:growth & development / Q000378:metabolism*; D010070:Oxalates / Q000378:metabolism*
D000085:Acetates; D010070:Oxalates