The column isoelectrofocusing activity of the nuclear extracts of the human cardiac muscle has revealed at pH 3.5-8.2 5 peaks of DNA-methylase. When one of these peaks (II) was analyzed by the two-dimensional gel electrophoresis 6 proteins (10, 25, 35, 43, 67 and 120 kDa) were separated. 43 kDa protein had electrophoretic properties similar to actins and was able to methylate cytosine in the DNA molecules. The comparative computer analysis of the primary structure of human actins and several bacterial DNA-methylases has shown the homology of the extensive fragments of these molecules.