[Heparin complexes with DNA: formation, properties and methylation in vitro].

Heparin complexes with DNA were obtained in vitro, the components being taken in weight ratios of 1 : 6 or 1 : 12, respectively. The complexes obtained exhibited the anticoagulating activity and antipolymerizing properties in the presence of a fibrin-monomer and an ability to dissolve nonstabilized fibrin. An intravenous injection of these complexes to rats increased the total and non-enzymatic fibrinolytic activity of blood plasma and its anticoagulating properties, while an intravenous injection of DNA caused only a short-term hypercoagulating effect. The DNA modified by heparin altered its acceptor abilities in an in vitro methylation reaction in the presence of DNA-methylases from animal and bacterial cells. Incorporation of methyl groups into DNA showed a decrease, apparently due to heparin blocking of some methylable sequences. An addition of heparin to a system containing purified DNA, DNA-methylase and S-adenosylmethionine was accompanied by a concentration-dependent inhibition of the methyl group incorporation into DNA.