BIOCHEMICAL PROPERTIES Ol- THE ISOLATED NUCLEUS 207 



droitin sulfate. All these compounds could restore some of the capacity for amino acid 

 incorporation into protein, or adenosine uptake into RNA. On the premise that the 

 removal of the DNA followed by a continued and prolonged incubation would lead to 

 instability and irreversible changes in the state of the chromosomes, attempts were 

 made to stabilize nuclear structure by substituting these polyanions for DNA at the 

 time of its removal. If this is done properly, it is possible to remove 76 per cent of the 

 DNA and replace it with polyethylene sulfonate (mol. wt. 12,900) without apparent 

 change in nuclear ability to take up amino acids into protein or adenosine into RNA. 

 Nor did we observe any impairment in nuclear ATP synthesis if DNA substitution by 

 polyethylene sulfonate was carried out rapidly. 



