The use of fluorine-containing carboxylic acids for the large-scale isolation of highly polymerized deoxyribonucleic acids.

1. The precipitation of the proteins of calf-thymus nucleohistone and herringsperm nucleoprotamine with the salts of fluorine-containing carboxylic acids has been studied. Pentadecafluoro-octanoate gave a precipitate that could be sedimented almost completely by centrifuging at 2350g for 20min. omega-H-Hexadecafluorononanoate, omega-H-eicosafluoro-undecanoate and dodecyl sulphate gave precipitates that could only be partly sedimented under these conditions. 2. A method has been developed for the isolation of highly polymerized DNA on a large scale from calf thymus and herring sperm by the use of pentadecafluorooctanoate. This is more convenient and less tedious than existing methods.