[The origin of 5 S DNA from tumor ascitic fluid]

Certain properties of DNA from chromatin mononucleosomes of the normal rat liver were compared with those of 5 S DNA from the ascitic fluids of human and animal tumours. Both DNA proved to be identical by their electrophoretic mobility in 8% PAAG and by characteristic violet tinge when stained with methylene blue. Thermal and alkaline denaturation causes less degradation of mononuclesome DNA than 5 S DNA. It is shown that 5 S DNA of ascitic fluid of Ehrlich ascite tumour of mice hybridizes with a higher amount of mouse genome DNA restricts. An assumption is advanced that 5 S DNA is either a product of chromatin decay to mononucleosomes or a product of extracopial synthesis and is delivered to ascitic fluid surrounding the tumour cells as a result of activation of Ca, Mg-dependent endonuclease of the latter.