[Changes in lactate dehydrogenase isoforms in the process of oncogenesis]. / Izmeneniia izoform laktatdegidrogenazy v protsesse onkogeneza.

Isoenzymes of lactate dehydrogenase were studied by disc-electrophoresis in polyacrylamide gel, and in the clinic--in 1% agar gel. Oncovirus A12 invasion of the culture of rat embryo fibroblasts (REF) was found to result in the increased percentage of the cathode fractions activity (LDG-4 and LD-5) and in the disappearance of LDG-1 yet during the first day of the experiment prior to hypoxia and enhanced proliferation, i. e. it is most likely to be primary. In the homogenates of cancerous tumor and large intestine polyps of man also a reliable increase of the cathode and a decrease or disappearance of the anode fractions accur. A correlation of the experimental and clinical data allowed a suggestion to be made that LDG isoenzymes changes are genetically conditioned and play an important role in the process of oncogenesis, providing conditions for the increased intensity of glycolysis and proliferation.

[Changes in the isoenzymatic spectrum of energy metabolism enzymes and in the mitochondrial ultrastructure in viral carcinogenesis]. / Izmeneniia izofermentnogo spektra nekotorykh fermentov énergeticheskogo obmena i ul'trastruktury mitokhondrii pri virusnom kantserogeneze.

The dynamics of redistribution of the isoenzymatic spectrum of lactate and malate dehydrogenases in the cells of rat embryo fibroblasts (REF) having been in contact with human adenovirus type 12, as compared to the dynamics of changes in the fine structure of the cellular mitochondria of the same models was studied. The action of oncogenic virus caused rearrangment in the isoenzymatic spectra of lactate and malate dehydrogenases both in the nuclei and in the cytoplasm. These disturbances occur from the first days of the REF culture interaction with the oncogenic virus and are not connected with the proliferative growth of the cell culture, but they are stipulated by the very fact of the virus influence on the cell. Comparison of the kinetics of the changes in the enzymes under study with the data of quantitative analysis of the fine structure of the mitochondrial apparatus demonstrated that biochemical shifts occurred much earlier, practically from the moment of infecting.

[Hexokinase activity in the soluble fraction of the nucleus and cytoplasm in cell cultures infected with human adenoviruses types 6 and 12]. / Aktivnost' geksokinazy v rastvorimoi fraktsii iadra i tsitoplazme kultur kletok, zarazhennykh adenovirusami tipov 6 i 12

A study was made of the activity of hexokinase in the soluble fraction of the nucleus and cytoplasm of fibroblasts of rat embryos (primary cultures) during contact with infectious (A6) and oncogenic (A12) human adenoviruses. A high activity of the enzyme was seen in the cytoplasmic fraction in comparison with the nuclear one both in the infectious adrenovirus of type 6 this value differed from the normal and in the experimental samples. With the action of the normal but insignificantly. Marked changes in the enzyme activity were observed in case of cell contact with the oncovirus. They occurred both in the nucleus and in the cytoplasm the first days of the virus inculcation, increasing gradually with the lapse of tiay; these disturbances were much greatert in the cytoplasm than in the nucleus. It is supposed that the changes revealed possibly associated with the impossibility to regulate the cell proliferation process.

[Activity of hexokinase isoenzymes in the nuclei of cell cultures infected with oncogenic type-12 adenovirus]. / Aktivnost' izoénzimov geksokinazy v iadrakh kul'tury kletok, infitsirovannykh onkogennym adenovirusom 12-go tipa

The isoenzymic spectrum of a glycolytic enzyme-hexokinase (HK. 2,7.1.1) in the globuline fraction of cell nuclei of rat embryo fibroblasts (REF), infected with human adenovirus of type 12, was studied at 3, 5, 8, 18, 24 days of cultivation. Control studies revealed 3 hexokinase isoenzymes, the third one showing the highest activity and electromobility. In cultures under experiment the first enzyme was found to be lost at 5, 8, 18 days of infection and its activity to be enhanced on the 24th day. The activity of enzymes II and III increased yet on the 3d day of the culture infection. These alterations were especially pronounced to the start of morphological transformation (18th day) and at the 24th day, when the culture was entirely transformed.

[Isoenzymes of lactate and malate dehydrogenases in nuclei of rat embryo fibroblasts infected with oncogenic adenovirus type 12]. / Izofermenty laktat- i malatdegidrogenazy v iadrakh fibroblastov embrionov krysy, zarazhennykh onkogennym adenovirusom tipa 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.