ISOENZYMES OF LACTATE-DEHYDROGENASES AND MALATE-DEHYDROGENASES IN NUCLEI OF RAT EMBRYO FIBROBLASTS INFECTED WITH ONCOGENIC ADENOVIRUS-TYPE-12

Abstract

The isoenzyme spectrum of lactate dehydrogenase (LDH, EC 1.1.1.27) and malate dehydrogenase (MDH, EC 1.1.1.37) in nuclei of rat embryo fibroblasts infected with adenovirus type 12 was studied 3, 5, 8, 18 and 24 days of cultivation. The nuclei were isolated according to the method of Showo et al. modified by Znarsky and Georgiev. Proteins were fractionated by disc electrophoresis in polyacrylamide gel. In the course of virus-cell interaction 3 LDH isoenzymes were detected. Changes in the isoenzyme spectrum of LDH were manifested in increased activity of LDH1 5 days after virus penetration into the cell. Partial morphological transformation 18 days after infection was accompanied by increased activity of LDH1 and LDH2. Morphologically transformed cells were characterized by reduced LDH1 activity. Changes in the spectrum of MDH isoenzymes were detected 3 days after addition of virus to the culture. At 24 days postinfection activity of MDH3 definitely changes in cell nuclei. The revealed disorders in regulation of synthesis of individual isoenzymes are probably due to the epigenomic effect of the virus and may be used as indications of tissue culture malignization.