[Isoenzymes of lactate and malate dehydrogenases in nuclei of rat embryo fibroblasts infected with oncogenic adenovirus type 12].

The isoenzymatic spectrum of lactatedehydrogenase (LDG; L-lactate: NAD-oxireductase; EC 1.1.1.27) and malatedehydrogenase (MDG; 1-malate: NAD-oxireductase; EC 1.1.1.37) in nuclei of rat embryo fibroblast cells infected with adenovirus type 12 was studied at 3, 5, 8, 18 and 24 days of cultivation. The nuclei were isolated according to the method of Showo et al. modified by Zbarsky and Georgiev. Proteins were fractionated by disc electrophoresis in polyacrylamide gel. In the course of oncovirus-cell interaction three LDG isoenzymes were detected. Changes in the isoenzymatic spectrum of LDG were manifested in increased activity of LDG1 at 5 days after virus penetration into the cell. Partial morphological transformation at 18 days after infection was accompanied by increased activity of LDG1 and LDG2. The morphologically transformed culture was characterised by reduced LDG1 activity. Changes in the spectrum of MDG isoenzymes were detected at 3 days after addition of A-12 virus into the culture. At 24 days postinfection activity of MDG3 was definitely changed in nuclei of REF cells infected with A-12 virus. The revealed disorders in regulation of synthesis of individual isoenzymes are probably due to the epigenomic effect of oncovirus and may be used as indications of tissue culture malignization.