Microbial metabolism of pyridinium compounds. Metabolism of 4-carboxy-1-methylpyridinium chloride, a photolytic product of paraquat.
1. A bacterium, Achromobacter D, isolated from garden soil by elective culture, utilized N-methylisonicotinic acid (4-carboxy-1-methylpyridinium chloride) as sole carbon source. 2. Extracts of N-methylisonicotinate-grown cells oxidized this substrate only after supplementation with a source of nicotinamide nucleotides and then consumed 1 mol of O(2) and released 1 mol of CO(2)/mol of N-methylisonicotinate supplied. 3. The N-methyl group of the substrate was released as methylamine whereas the five C atoms of the pyridine ring were accounted for as succinate and formate. The CO(2) evolved by extracts was believed to derive from the carboxyl group on C-4 of the heterocyclic ring. 4. The immediate precursor of the succinate end-product was succinic semialdehyde; the inducible nature of succinic semialdehyde dehydrogenase in N-methylisonicotinate-grown cells supported this finding. 5. There was no evidence for monohydroxylation of the ring, but the time sequence of the appearance of the end-products indicated that the oxygen-requiring, NADH-requiring and decarboxylation steps clearly preceded the formation of methylamine and succinate. 6. The results are consistent with the oxidative cleavage of a partially reduced heterocyclic ring followed by several hydrolytic and dehydrogenase steps resulting in the appearance of the end-products.
D000421:Alcaligenes / Q000378:metabolism*; D000445:Aldehyde Oxidoreductases / Q000378:metabolism; D002474:Cell-Free System; D003653:Decarboxylation; D005561:Formates / Q000378:metabolism; D006868:Hydrolysis; D006900:Hydroxylation; D007539:Isonicotinic Acids / Q000378:metabolism*; D008365:Manometry; D008744:Methylamines / Q000378:metabolism; D009243:NAD / Q000378:metabolism; D009249:NADP / Q000378:metabolism; D010084:Oxidation-Reduction; D010101:Oxygen Consumption; D010269:Paraquat; D010782:Photolysis; D012988:Soil Microbiology; D013053:Spectrophotometry; D013386:Succinates / Q000378:metabolism
D005561:Formates; D007539:Isonicotinic Acids; D008744:Methylamines; D013386:Succinates; D009243:NAD; D009249:NADP; D000445:Aldehyde Oxidoreductases; D010269:Paraquat