title: Working with "H2S": facts and apparent artifacts.
abstract: Hydrogen sulfide (H2S) is an important signaling molecule with physiological endpoints similar to those of nitric oxide (NO). Growing interest in its physiological roles and pharmacological potential has led to large sets of contradictory data. The principle cause of these discrepancies can be the common neglect of some of the basic H2S chemistry. This study investigates how the experimental outcome when working with H2S depends on its source and dose and the methodology employed. We show that commercially available NaHS should be avoided and that traces of metal ions should be removed because these can reduce intramolecular disulfides and change protein structure. Furthermore, high H2S concentrations may lead to a complete inhibition of cell respiration, mitochondrial membrane potential depolarization and superoxide generation, which should be considered when discussing the biological effects observed upon treatment with high concentrations of H2S. In addition, we provide chemical evidence that H2S can directly react with superoxide. H2S is also capable of reducing cytochrome c(3+) with the concomitant formation of superoxide. H2S does not directly react with nitrite but with NO electrodes that detect H2S. In addition, H2S interferes with the Griess reaction and should therefore be removed from the solution by Cd(2+) or Zn(2+) precipitation prior to nitrite quantification. 2-Phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide (PTIO) is reduced by H2S, and its use should be avoided in combination with H2S. All these constraints must be taken into account when working with H2S to ensure valid data.
authors.affiliation: Department of Chemistry and Pharmacy, University of Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: Rudolf
authors.initials: R
authors.lastname: Wedmann
authors.affiliation: Department of Chemistry and Pharmacy, University of Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: Sarah
authors.initials: S
authors.lastname: Bertlein
authors.affiliation: Department of Chemistry and Pharmacy, University of Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: Igor
authors.initials: I
authors.lastname: Macinkovic
authors.affiliation: Medical Clinic 3 - Rheumatology and Immunology, University of Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Böltz
authors.affiliation: Department of Chemistry and Pharmacy, University of Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: Jan Lj
authors.initials: JLj
authors.lastname: Miljkovic
authors.affiliation: Medical Clinic 3 - Rheumatology and Immunology, University of Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: Luis E
authors.initials: LE
authors.lastname: Muñoz
authors.affiliation: Medical Clinic 3 - Rheumatology and Immunology, University of Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Herrmann
authors.affiliation: Department of Chemistry and Pharmacy, University of Erlangen-Nuremberg, Erlangen, Germany. Electronic address: milos.filipovic@fau.de.
authors.forename: Milos R
authors.initials: MR
authors.lastname: Filipovic
mesh_terms: D016477:Artifacts; D045744:Cell Line, Tumor; D003497:Cyclic N-Oxides / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D006862:Hydrogen Sulfide / Q000032:analysis / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology*; D007093:Imidazoles / Q000737:chemistry / Q000378:metabolism; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D009569:Nitric Oxide / Q000032:analysis; D012107:Research Design / Q000592:standards*; D013481:Superoxides / Q000737:chemistry / Q000378:metabolism
chemical_list: D003497:Cyclic N-Oxides; D007093:Imidazoles; D013481:Superoxides; C079391:2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide; D009569:Nitric Oxide; D006862:Hydrogen Sulfide
keywords: Cytochrome c; Hydrogen sulfide; Nitric oxide; Nitrite; Polysulfides; Superoxide