Initial steps in the fermentation of 3-hydroxybenzoate by Sporotomaculum hydroxybenzoicum.
The anaerobic bacterium Sporotomaculum hydroxybenzoicum ferments 3-hydroxybenzoate to acetate, butyrate, and CO2. 3-Hydroxybenzoate was activated to 3-hydroxybenzoyl-CoA in a CoA-transferase reaction with acetyl-CoA or butyryl-CoA as CoA donors. 3-Hydroxybenzoyl-CoA was reductively dehydroxylated, forming benzoyl-CoA. This reaction was measured in cell-free extracts with cob(I)alamin as low-potential electron donor. No evidence was obtained that cob(I)alamin is the physiological electron donor; however, inhibitor studies indicated involvement of a strong nucleophile in the reaction. Benzoate was degraded by dense cell suspensions without a lag phase until an in situ deltaG' value <-25 kJ mol(-1) was reached. Benzoyl-CoA reductase was not detected. Enzyme activities for all reaction steps from glutaryl-CoA to butyryl-CoA, and ATP formation via acetate kinase were detected in cell-free extracts. Glutaconyl-CoA decarboxylase is likely to act as a primary sodium ion pump.
Müller
J A
JA
Fakultät für Biologie, Universität Konstanz, Germany. jochen_mueller@hotmail.com
Schink
B
B
D000214:Acyl Coenzyme A / Q000378:metabolism; D000477:Alkylating Agents / Q000494:pharmacology; D001421:Bacteria, Anaerobic / Q000201:enzymology / Q000254:growth & development / Q000378:metabolism*; D001565:Benzoates / Q000378:metabolism; D001673:Biodegradation, Environmental; D005285:Fermentation; D062385:Hydroxybenzoates / Q000378:metabolism*; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000378:metabolism; D044925:Oxidoreductases Acting on CH-CH Group Donors
D000214:Acyl Coenzyme A; D000477:Alkylating Agents; D001565:Benzoates; D062385:Hydroxybenzoates; C032948:3-hydroxybenzoic acid; C037817:benzoyl-coenzyme A; D010088:Oxidoreductases; D044925:Oxidoreductases Acting on CH-CH Group Donors; C109030:benzoyl-coenzyme A reductase (dearomatizing)