title: Fermentation of fructose and synthesis of acetate from carbon dioxide by Clostridium formicoaceticum.
abstract: Clostridium formicoaceticum ferments fructose labeled with (14)C in carbon 1, 4, 5, or 6 via the Embden Meyerhof pathway. In fermentations of fructose in the presence of (14)CO(2), acetate is formed labeled equally in both carbons. Extracts convert the methyl groups of 5-methyltetrahydrofolate and methyl-B(12) to the methyl group of acetate in the presence of pyruvate. Formate dehydrogenase, 10-formyltetrahydrofolate synthetase, 5,10-methenyltetrahydrofolate cyclohydrolase, 5,10-methylenetetrahydrofolate dehydrogenase, and 5,10-methylenetetrahydrofolate reductase are present in extracts of C. formicoaceticum. These enzymes are needed for the conversion of CO(2) to 5-methyltetrahydrofolate. It is proposed that acetate is totally synthesized from CO(2) via the reactions catalyzed by the enzymes listed above and that 5-methyltetra-hydrofolate and a methylcorrinoid are intermediates in this synthesis.
mesh_terms: D000085:Acetates / Q000096:biosynthesis*; D000619:Aminohydrolases / Q000378:metabolism; D001639:Bicarbonates / Q000378:metabolism; D002245:Carbon Dioxide / Q000378:metabolism*; D002247:Carbon Isotopes; D002474:Cell-Free System; D003013:Clostridium / Q000201:enzymology / Q000254:growth & development / Q000378:metabolism*; D003470:Culture Media; D005285:Fermentation; D005492:Folic Acid / Q000096:biosynthesis / Q000378:metabolism; D005561:Formates; D005632:Fructose / Q000378:metabolism*; D008025:Ligases / Q000378:metabolism; D010088:Oxidoreductases / Q000378:metabolism; D013053:Spectrophotometry; D014805:Vitamin B 12 / Q000378:metabolism
chemical_list: D000085:Acetates; D001639:Bicarbonates; D002247:Carbon Isotopes; D003470:Culture Media; D005561:Formates; D002245:Carbon Dioxide; D005632:Fructose; D005492:Folic Acid; D010088:Oxidoreductases; D000619:Aminohydrolases; D008025:Ligases; D014805:Vitamin B 12