Homogeneous preparations of liver glutathione reductase (GR, EC 1.6.4.2.), obtained from control rats and animals with toxic hepatitis, catalytic properties of this enzyme have been investigated. A number of the enzyme properties did not change under conditions of hepatitis. These included electrophoretic mobility (R(f) = 0.23 +/- 0.01), molecular mass (104 +/- 5.20 kDa), pH-optimum (7.4 +/- 0.37). There was similarity in pK values of functional groups. At the same time, decrease in affinity of enzyme to a substrate and coenzyme and occurrence substrate-linked inhibition was observed under conditions of this pathology. There were some differencies in regulation of GR activity by metabolites of tricarboxylic acid cycle.