title: Dimethylsulfoxide oxidizes glutathione in vitro and in human erythrocytes: kinetic analysis by 1H NMR.
abstract: The interaction of dimethylsulfoxide (Me2SO) with glutathione was investigated under non-equilibrium conditions in solution using 1H NMR and in intact erythrocytes using 1H spin-echo NMR. In solution the reaction was observed to follow second-order kinetics (Rate = k1[glutathione][Me2SO]) at 300 K pH 7.4, k(sol) = 4.7 x 10(-5)mol(-1)L(1)s(-1). In intact erythrocytes the rate constant for the cellular environment, k(cell), was found to be slightly larger at 8.1 x 10(-5)mol(-1)L(1)s(-1). Furthermore, the reaction of Me2SO with erythrocyte glutathione showed a biphasic dependence on the Me2SO concentration, with little oxidation of glutathione occurring until the Me2SO concentration exceeded 0.5 molL(-1). The results suggest that at lower concentrations, Me2SO can be effectively removed, most probably by reaction with glutathione, which is regenerated by glutathione reductase, although preferential reaction with other cellular components (e.g., membrane or cellular thiols) cannot be ruled out. Thus the concentrations of Me2SO that are commonly used in cryopreservation of mammalian cells ( approximately 1.4 molL(-1)) can cause oxidation of intracellular glutathione.
authors.affiliation: Department of Pure and Applied Chemistry, Strathclyde University, 295 Cathedral Street, Glasgow G1 1XL, UK.
authors.forename: Natalie Z M
authors.initials: NZ
authors.lastname: Homer
authors.forename: John
authors.initials: J
authors.lastname: Reglinski
authors.forename: Rebecca
authors.initials: R
authors.lastname: Sowden
authors.forename: Corinne M
authors.initials: CM
authors.lastname: Spickett
authors.forename: Rhoda
authors.initials: R
authors.lastname: Wilson
authors.forename: James J
authors.initials: JJ
authors.lastname: Walker
mesh_terms: D015925:Cryopreservation; D003451:Cryoprotective Agents / Q000737:chemistry*; D004121:Dimethyl Sulfoxide / Q000737:chemistry*; D005978:Glutathione / Q000737:chemistry*; D006801:Humans; D066298:In Vitro Techniques; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D010084:Oxidation-Reduction
chemical_list: D003451:Cryoprotective Agents; D005978:Glutathione; D004121:Dimethyl Sulfoxide