THE CONTENT OF GLUTATHIONE AND GLUTATHIONE S-TRANSFERASES AND THE GLUTATHIONE-PEROXIDASE ACTIVITY IN RAT-LIVER NUCLEI DETERMINED BY A NONAQUEOUS TECHNIQUE OF CELL FRACTIONATION

Hepatocellular nuclei require glutathione, glutathione S-transferases (GSTs) and Se-dependent glutathione peroxidase (GPx) for intranuclear protection against damage from electrophiles or products of active oxy gen. Data so far available from the literature on nuclei isolated in a queous systems range from glutathione, GSTs and GPx either being absen t altogether to being present in quantities in excess of those in the cytoplasm. This paper describes a small-scale preparation of a nuclear fraction from rat liver by a non-aqueous technique, designed to retai n nuclear water-soluble molecules in situ, since low-molecular-mass co mpounds can diffuse freely into other compartments during aqueous sepa ration. This non-aqueous procedure shows the nucleus to contain glutat hione at 8.4 mM and soluble GSTs at 38 mu g/mg of protein, the enrichm ent over the homogenate being 1.2-1.4-fold. Se-dependent GPx activity was also present in the nucleus (56 m-units/mg), although with slightl y lower activity than in the homogenate (0.7-fold).