title: Mechanism of strong resistance of Helicobacter pylori respiration to nitric oxide.
abstract: The aim of the present work is to elucidate the mechanism by which the respiration of Helicobacter pylori but not of Escherichia coli shows a strong resistance to nitric oxide (NO). Nitric oxide strongly but reversibly inhibited the oxygen consumption by sonicated membranes from H. pylori and Triton X-100-treated cells. Although the sensitivity of the H. pylori respiration to cyanide was low, it also increased after the treatment with Triton X-100. Kinetic analyses revealed that NO was rapidly degraded by E. coli and the Triton X-100-treated H. pylori, but not by the intact H. pylori. Thus, the low sensitivity to NO might reflect the low affinity of the cytochrome c oxidase for this radical within the membrane/lipid bilayers of H. pylori. Such properties of the oxidase in H. pylori membranes may, at least in part, underlie the mechanism by which this bacterium thrives in NO-enriched gastric juice.
authors.affiliation: Department of Biochemistry and Molecular Pathology, Osaka City University Medical School, 1-4-3 Asahimachi, Abeno, 545-8585, Osaka, Japan.
authors.forename: Ah-Mee
authors.initials: AM
authors.lastname: Park
authors.forename: Kumiko
authors.initials: K
authors.lastname: Nagata
authors.forename: Eisuke F
authors.initials: EF
authors.lastname: Sato
authors.forename: Toshihide
authors.initials: T
authors.lastname: Tamura
authors.forename: Kunio
authors.initials: K
authors.lastname: Shimono
authors.forename: Masayasu
authors.initials: M
authors.lastname: Inoue
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D024881:Drug Resistance, Bacterial; D004926:Escherichia coli / Q000187:drug effects / Q000378:metabolism; D016480:Helicobacter pylori / Q000187:drug effects* / Q000378:metabolism; D007700:Kinetics; D010101:Oxygen Consumption / Q000187:drug effects*; D013045:Species Specificity
chemical_list: D000255:Adenosine Triphosphate