There were investigated the epigenetic changes of the enzyme proteins in the tissues of animals after ionizing radiation. Changes in the dynamics of containing LDH isozymes during the experiment were determined. This demonstrates the instability of epigenetic formation of enzyme tetramers. Total LDH4 and LDH5 activity in tissues of irradiated animals was lower than activity of isozymes in intact animals in the first three days and it was higher in the next term throughout all research terms. This dynamics of LDH isozymes in myocardium and skeletal muscles of irradiated animals reflect not only development of tissue hypoxia, but the disturbance of epigenetic assembly of enzyme tetramers.
