Kinetics of the reaction between nitric oxide and glutathione: implications for thiol depletion in cells.
Nitric oxide in the absence of oxygen was suggested to react with 5-50 mM glutathione (GSH) over many minutes when [NO*] << [GSH] (N. Hogg et al., FEBS Lett. 382:223-228; 1996). However, Aravindakumar et al. (J. Chem. Soc. Perkin Trans. 2:663-669; 2002) provided data suggesting approxi...
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| Format: | Journal article |
| Language: | English |
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2004
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| _version_ | 1797103211141660672 |
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| author | Folkes, L Wardman, P |
| author_facet | Folkes, L Wardman, P |
| author_sort | Folkes, L |
| collection | OXFORD |
| description | Nitric oxide in the absence of oxygen was suggested to react with 5-50 mM glutathione (GSH) over many minutes when [NO*] << [GSH] (N. Hogg et al., FEBS Lett. 382:223-228; 1996). However, Aravindakumar et al. (J. Chem. Soc. Perkin Trans. 2:663-669; 2002) provided data suggesting approximately 200-fold higher reactivity under conditions of [NO*] >> [GSH]. To help resolve these differences, the rate of loss of NO* ( approximately 9 microM) in aqueous solutions of GSH (2.5-20 mM) was measured by chemiluminescence. An apparent second-order rate constant of 0.080 +/- 0.008 M(-1) s(-1) at pH 7.4, 37 degrees C, was calculated based on the total [GSH] and "pseudo-first-order" kinetics; thiolate anion was much more reactive than undissociated thiol. These data imply a half-life of approximately 30 min for low concentrations of NO* with 5 mM GSH, 37 degrees C, pH 7.4, in the absence of oxygen. Possible kinetic schemes that can partially explain the divergent literature reports are discussed, notably an equilibrium in the reaction between NO* and GSH. Human breast carcinoma MCF-7 cells were exposed to NO* (initially approximately 18 microM) in alidded six well plate in an anaerobic chamber in vitro; intracellular GSH levels decreased by half in approximately 60 min. Aerobic exposure depletes GSH in cells in vitro much faster because of autoxidation of NO* to NO2*, >10(8) times more reactive toward GSH. |
| first_indexed | 2024-03-07T06:16:50Z |
| format | Journal article |
| id | oxford-uuid:f15b7e6b-c7b0-4eb7-9bff-6c81f3063973 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T06:16:50Z |
| publishDate | 2004 |
| record_format | dspace |
| spelling | oxford-uuid:f15b7e6b-c7b0-4eb7-9bff-6c81f30639732022-03-27T11:55:25ZKinetics of the reaction between nitric oxide and glutathione: implications for thiol depletion in cells.Journal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:f15b7e6b-c7b0-4eb7-9bff-6c81f3063973EnglishSymplectic Elements at Oxford2004Folkes, LWardman, PNitric oxide in the absence of oxygen was suggested to react with 5-50 mM glutathione (GSH) over many minutes when [NO*] << [GSH] (N. Hogg et al., FEBS Lett. 382:223-228; 1996). However, Aravindakumar et al. (J. Chem. Soc. Perkin Trans. 2:663-669; 2002) provided data suggesting approximately 200-fold higher reactivity under conditions of [NO*] >> [GSH]. To help resolve these differences, the rate of loss of NO* ( approximately 9 microM) in aqueous solutions of GSH (2.5-20 mM) was measured by chemiluminescence. An apparent second-order rate constant of 0.080 +/- 0.008 M(-1) s(-1) at pH 7.4, 37 degrees C, was calculated based on the total [GSH] and "pseudo-first-order" kinetics; thiolate anion was much more reactive than undissociated thiol. These data imply a half-life of approximately 30 min for low concentrations of NO* with 5 mM GSH, 37 degrees C, pH 7.4, in the absence of oxygen. Possible kinetic schemes that can partially explain the divergent literature reports are discussed, notably an equilibrium in the reaction between NO* and GSH. Human breast carcinoma MCF-7 cells were exposed to NO* (initially approximately 18 microM) in alidded six well plate in an anaerobic chamber in vitro; intracellular GSH levels decreased by half in approximately 60 min. Aerobic exposure depletes GSH in cells in vitro much faster because of autoxidation of NO* to NO2*, >10(8) times more reactive toward GSH. |
| spellingShingle | Folkes, L Wardman, P Kinetics of the reaction between nitric oxide and glutathione: implications for thiol depletion in cells. |
| title | Kinetics of the reaction between nitric oxide and glutathione: implications for thiol depletion in cells. |
| title_full | Kinetics of the reaction between nitric oxide and glutathione: implications for thiol depletion in cells. |
| title_fullStr | Kinetics of the reaction between nitric oxide and glutathione: implications for thiol depletion in cells. |
| title_full_unstemmed | Kinetics of the reaction between nitric oxide and glutathione: implications for thiol depletion in cells. |
| title_short | Kinetics of the reaction between nitric oxide and glutathione: implications for thiol depletion in cells. |
| title_sort | kinetics of the reaction between nitric oxide and glutathione implications for thiol depletion in cells |
| work_keys_str_mv | AT folkesl kineticsofthereactionbetweennitricoxideandglutathioneimplicationsforthioldepletionincells AT wardmanp kineticsofthereactionbetweennitricoxideandglutathioneimplicationsforthioldepletionincells |