28 



MAURICE J. BESSMAN 



By these criteria, natural DNA and the j^roduct synthesized with 

 E. coli polymerase are identical, 



2. Physical Structure 



Pliysical nioasiirenients of the DNA synthesized by E. coli polymerase 

 became feasible when net synthesis of product was accomplished. In 

 Table XI, several preparations of DNA are shown in which increases 



TABLE XII 

 Physical Properties of Enzymatically Synthesized DNA" 



° From Lehman (1959). 



up to 20 times that of the added primer indicate that at least 95% of the 

 total DNA represents newly synthesized material. These products were 



Time in Hours 



Fig. 8. Increase in ultraviolet absoriition of DNA upon digestion with pancreatic 

 deoxyribonuclease. (From Lehman, 1959.) 



