Divergent metabolic pathways for propane and propionate utilization by a soil isolate.
The metabolism of propane and propionate by a soil isolate (Brevibacterium sp. strain JOB5) was investigated. The presence of isocitrate lyase in cells grown on isopropanol, acetate, or propane and the absence of this inducible enzyme in n-propanol- and propionate-grown cells suggested that propane is not metabolized via C-terminal oxidation. Methylmalonyl coenzyme A mutase and malate synthase are constitutive in this organism. The incorporation of (14)CO(2) into pyruvate accumulated during propionate utilization suggests that propionate is metabolized via the methyl-malonyl-succinate pathway. These results were further substantiated by radiorespirometric studies with propionate-1-(14)C, -2-(14)C, and -3-(14)C as substrate. Propane -2-(14)C was shown, by unlabeled competitor experiments, to be oxidized to acetone; acetone and isopropanol are oxidized in this organism to acetol. Cleavage of acetol to acetate and CO(2) would yield the inducer for the isocitrate lyase present in propane-grown cells.
D000473:Alkanes / Q000378:metabolism*; D001419:Bacteria / Q000378:metabolism*; D001951:Brevibacterium / Q000201:enzymology / Q000378:metabolism; D002245:Carbon Dioxide / Q000378:metabolism; D002247:Carbon Isotopes; D007535:Isomerases / Q000378:metabolism; D008190:Lyases / Q000378:metabolism; D011422:Propionates / Q000378:metabolism*; D011773:Pyruvates / Q000096:biosynthesis; D012988:Soil Microbiology
D000473:Alkanes; D002247:Carbon Isotopes; D011422:Propionates; D011773:Pyruvates; D002245:Carbon Dioxide; D008190:Lyases; D007535:Isomerases