title: Mathematically combined half-cell reduction potentials of low-molecular-weight thiols as markers of seed ageing.
abstract: The half-cell reduction potential of the glutathione disulphide (GSSG)/glutathione (GSH) redox couple appears to correlate with cell viability and has been proposed to be a marker of seed viability and ageing. This study investigated the relationship between seed viability and the individual half-cell reduction potentials (E(i)s) of four low-molecular-weight (LMW) thiols in Lathyrus pratensis seeds subjected to artificial ageing: GSH, cysteine (Cys), cysteinyl-glycine (Cys-Gly) and γ-glutamyl-cysteine (γ-Glu-Cys). The standard redox potential of γ-Glu-Cys was previously unknown and was experimentally determined. The E(i)s were mathematically combined to define a LMW thiol-disulphide based redox environment (E(thiol-disulphide)). Loss of seed viability correlated with a shift in E(thiol-disulphide) towards more positive values, with a LD(50) value of -0.90 ± 0.093 mV M (mean ± SD). The mathematical definition of E(thiol-disulphide) is envisaged as a step towards the definition of the overall cellular redox environment, which will need to include all known redox-couples.
authors.affiliation: Seed Conservation Department, Royal Botanic Gardens, Kew, Wakehurst Place, West Sussex, UK.
authors.forename: Simona
authors.initials: S
authors.lastname: Birtić
authors.forename: Louise
authors.initials: L
authors.lastname: Colville
authors.forename: Hugh W
authors.initials: HW
authors.lastname: Pritchard
authors.forename: Stephen R
authors.initials: SR
authors.lastname: Pearce
authors.forename: Ilse
authors.initials: I
authors.lastname: Kranner
mesh_terms: D015415:Biomarkers / Q000737:chemistry / Q000378:metabolism; D016922:Cellular Senescence; D003545:Cysteine / Q000737:chemistry / Q000378:metabolism; D005978:Glutathione / Q000737:chemistry / Q000378:metabolism*; D019803:Glutathione Disulfide / Q000737:chemistry / Q000378:metabolism*; D027807:Lathyrus / Q000737:chemistry / Q000502:physiology*; D008970:Molecular Weight; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D012639:Seeds / Q000737:chemistry / Q000502:physiology*; D013438:Sulfhydryl Compounds / Q000737:chemistry / Q000378:metabolism*
chemical_list: D015415:Biomarkers; D013438:Sulfhydryl Compounds; D005978:Glutathione; D003545:Cysteine; D019803:Glutathione Disulfide