title: Rapid Method for the Quantification of Reduced and Oxidized Glutathione in Human Plasma and Saliva.
abstract: A new method is developed to determine the concentrations of reduced (GSH) and oxidized glutathione (GSSG), and it enables the calculation of the GSH:GSSG ratios in human plasma and saliva samples. The assay is based on the masking of GSH in a GSH and GSSG mixture via a 1,4-addition reaction with p-benzoquinone (BQ), followed by enzymatic kinetic measurement. The enzyme, glutathione reductase, is highly specific to glutathione. Excess BQ can thus be easily removed by the addition of non-GSH thiols. The assay takes less than 2 min, is suitable for a short-time-scale study, and minimizes the in vitro underestimation of the GSH:GSSG ratio arising from the degradation of GSH and formation of GSSG. We further show in this paper that the stability of the total glutathione content (GSH + GSSG) and GSH in saliva is significantly greater than in plasma, encouraging the development of noninvasive saliva sensing.
authors.affiliation: Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford , South Parks Road, Oxford OX1 3QZ, United Kingdom.
authors.forename: Kamonwad
authors.initials: K
authors.lastname: Ngamchuea
authors.affiliation: Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford , South Parks Road, Oxford OX1 3QZ, United Kingdom.
authors.forename: Christopher
authors.initials: C
authors.lastname: Batchelor-McAuley
authors.affiliation: Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford , South Parks Road, Oxford OX1 3QZ, United Kingdom.
authors.forename: Richard G
authors.identifier: 0000-0001-9841-5041
authors.initials: RG
authors.lastname: Compton
mesh_terms: D016227:Benzoquinones / Q000737:chemistry; D057075:Enzyme Assays; D005978:Glutathione / Q000032:analysis* / Q000097:blood / Q000378:metabolism; D019803:Glutathione Disulfide / Q000032:analysis* / Q000097:blood / Q000378:metabolism; D005980:Glutathione Reductase / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D012463:Saliva / Q000378:metabolism*; D013696:Temperature
chemical_list: D016227:Benzoquinones; C004532:quinone; D005980:Glutathione Reductase; D005978:Glutathione; D019803:Glutathione Disulfide