Catabolic enzymes of the acetogen Butyribacterium methylotrophicum grown on single-carbon substrates.
When grown on formate, formate-CO, and methanol-CO, Butyribacterium methylotrophicum contained high levels of tetrahydrofolate (H4folate) and required enzymes, carbon monoxide dehydrogenase, formate dehydrogenase, and hydrogenase. The activities of methylene-H4folate reductase were comparable to other H4 folate activities (which ranged from 0.55 to 9.28 mumol/min per mg of protein) when measured by an improved procedure. The H4folate activities in formate-grown cells were twice those found in formate-CO-grown cells. This result correlated with a growth yield on formate that was one-half that on formate-CO. The stoichiometry of the formyl-H4folate synthetase reaction was 1 mol of ATP per 1 mol of formate. The methylene-H4folate dehydrogenase was NAD+ dependent. We conclude that B. methylotrophicum utilizes these enzymes in homoacetogenic catabolism.
Kerby
R
R
Department of Bacteriology, University of Wisconsin, Madison 53706.
Zeikus
J G
JG
D000445:Aldehyde Oxidoreductases / Q000378:metabolism; D002248:Carbon Monoxide / Q000378:metabolism; D005051:Eubacterium / Q000201:enzymology* / Q000254:growth & development; D005560:Formate Dehydrogenases / Q000378:metabolism; D005561:Formates / Q000378:metabolism; D006864:Hydrogenase / Q000378:metabolism; D000432:Methanol / Q000378:metabolism; D042965:Methylenetetrahydrofolate Reductase (NADPH2); D009097:Multienzyme Complexes; D010088:Oxidoreductases / Q000378:metabolism*; D000587:Oxidoreductases Acting on CH-NH Group Donors / Q000378:metabolism; D013763:Tetrahydrofolates / Q000378:metabolism*
D005561:Formates; D009097:Multienzyme Complexes; D013763:Tetrahydrofolates; D002248:Carbon Monoxide; D010088:Oxidoreductases; D006864:Hydrogenase; D005560:Formate Dehydrogenases; D000445:Aldehyde Oxidoreductases; C019823:carbon monoxide dehydrogenase; D000587:Oxidoreductases Acting on CH-NH Group Donors; D042965:Methylenetetrahydrofolate Reductase (NADPH2); D000432:Methanol