title: Proton translocation coupled to nitrite reduction in anaerobically grown Escherichia coli.
abstract: Proton translocation coupled to the reduction of nitrite was studied in anaerobically grown Escherichia coli. Extrusion of protons occurred by adding nitrite to an anaerobic suspension of wild-type cells. This extrusion was sensitive to a proton conductor, 3,5-di-tert-butyl-4-hydroxybenzylidenemalononitrile (SF6847) or carbonylcyanide-p-trifluoromethoxyphenylhydrazone. Dicyclohexylcarbodiimide, an inhibitor of H+-ATPase, prevented the proton extrusion linked to nitrite reduction, whereas this reagent had no effect on respiratory nitrate reduction to nitrite. Proton extrusion was undetectable when nitrite was added to a suspension of mutant cells defective in H+-ATPase. These results indicate that the proton extrusion associated with nitrite reduction to ammonia is not by redox pumps but by H+-ATPase. From the results obtained by the measurement of proton extrusion in nitrite reductase-deficient mutants, NADH-nitrite reductase system is suggested to involve the proton extrusion in whole cells of E. coli.
authors.forename: M T
authors.initials: MT
authors.lastname: Sawada
authors.forename: M
authors.initials: M
authors.lastname: Ishimoto
mesh_terms: D000641:Ammonia / Q000378:metabolism; D000693:Anaerobiosis; D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone / Q000494:pharmacology; D004926:Escherichia coli / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007476:Ionophores; D009154:Mutation; D009570:Nitriles / Q000494:pharmacology; D050898:Nitrite Reductase (NAD(P)H); D009572:Nitrite Reductases / Q000378:metabolism; D009573:Nitrites / Q000378:metabolism*; D010084:Oxidation-Reduction; D006180:Proton-Translocating ATPases / Q000378:metabolism; D011522:Protons
chemical_list: D007476:Ionophores; D009570:Nitriles; D009573:Nitrites; D011522:Protons; D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone; C001784:SF 6847; D000641:Ammonia; D009572:Nitrite Reductases; D050898:Nitrite Reductase (NAD(P)H); D006180:Proton-Translocating ATPases