title: Cyanide degradation by Pseudomonas pseudoalcaligenes CECT5344 involves a malate:quinone oxidoreductase and an associated cyanide-insensitive electron transfer chain.
abstract: The alkaliphilic bacterium Pseudomonas pseudoalcaligenes CECT5344 is able to grow with cyanide as the sole nitrogen source. Membrane fractions from cells grown under cyanotrophic conditions catalysed the production of oxaloacetate from L-malate. Several enzymic activities of the tricarboxylic acid and glyoxylate cycles in association with the cyanide-insensitive respiratory pathway seem to be responsible for the oxaloacetate formation in vivo. Thus, in cyanide-grown cells, citrate synthase and isocitrate lyase activities were significantly higher than those observed with other nitrogen sources. Malate dehydrogenase activity was undetectable, but a malate:quinone oxidoreductase activity coupled to the cyanide-insensitive alternative oxidase was found in membrane fractions from cyanide-grown cells. Therefore, oxaloacetate production was linked to the cyanide-insensitive respiration in P. pseudoalcaligenes CECT5344. Cyanide and oxaloacetate reacted chemically inside the cells to produce a cyanohydrin (2-hydroxynitrile), which was further converted to ammonium. In addition to cyanide, strain CECT5344 was able to grow with several cyano derivatives, such as 2- and 3-hydroxynitriles. The specific system required for uptake and metabolization of cyanohydrins was induced by cyanide and by 2-hydroxynitriles, such as the cyanohydrins of oxaloacetate and 2-oxoglutarate.
authors.affiliation: Departamento de Bioquímica y Biología Molecular, Campus de Rabanales, Edificio Severo Ochoa, 1a Planta, Universidad de Córdoba, Córdoba, Spain.
authors.forename: Victor M
authors.initials: VM
authors.lastname: Luque-Almagro
authors.affiliation: Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Veterinaria, Universidad de Extremadura, Cáceres, Spain.
authors.forename: Faustino
authors.initials: F
authors.lastname: Merchán
authors.affiliation: Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Veterinaria, Universidad de Extremadura, Cáceres, Spain.
authors.forename: Rafael
authors.initials: R
authors.lastname: Blasco
authors.affiliation: Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Veterinaria, Universidad de Extremadura, Cáceres, Spain.
authors.forename: M Isabel
authors.initials: MI
authors.lastname: Igeño
authors.affiliation: Departamento de Bioquímica y Biología Molecular, Campus de Rabanales, Edificio Severo Ochoa, 1a Planta, Universidad de Córdoba, Córdoba, Spain.
authors.forename: Manuel
authors.initials: M
authors.lastname: Martínez-Luque
authors.affiliation: Departamento de Bioquímica y Biología Molecular, Campus de Rabanales, Edificio Severo Ochoa, 1a Planta, Universidad de Córdoba, Córdoba, Spain.
authors.forename: Conrado
authors.initials: C
authors.lastname: Moreno-Vivián
authors.affiliation: Departamento de Bioquímica y Biología Molecular, Campus de Rabanales, Edificio Severo Ochoa, 1a Planta, Universidad de Córdoba, Córdoba, Spain.
authors.forename: Francisco
authors.initials: F
authors.lastname: Castillo
authors.affiliation: Departamento de Bioquímica y Biología Molecular, Campus de Rabanales, Edificio Severo Ochoa, 1a Planta, Universidad de Córdoba, Córdoba, Spain.
authors.forename: M Dolores
authors.initials: MD
authors.lastname: Roldán
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism; D001673:Biodegradation, Environmental; D003470:Culture Media; D003486:Cyanides / Q000378:metabolism* / Q000494:pharmacology; D004579:Electron Transport / Q000187:drug effects*; D008293:Malates / Q000378:metabolism; D009570:Nitriles / Q000378:metabolism; D062907:Oxaloacetic Acid / Q000378:metabolism; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000378:metabolism*; D010101:Oxygen Consumption; D044205:Pseudomonas pseudoalcaligenes / Q000201:enzymology / Q000254:growth & development / Q000378:metabolism*; D000644:Quaternary Ammonium Compounds / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D003470:Culture Media; D003486:Cyanides; D008293:Malates; D009570:Nitriles; D000644:Quaternary Ammonium Compounds; C430593:cyanohydrin; D062907:Oxaloacetic Acid; C030298:malic acid; D010088:Oxidoreductases; C471971:malate dehydrogenase, FAD-dependent