METABOLISM OF THE NUCLEIC ACIDS 



409 



40 



> 30 



9. 20 



10 



2 4 



8 10 12 14 16 

 Time in hours 



18 20 22 24 



Fig. 1. Relative specific activities of the inorganic phosphate, nuclear PNA. 

 and microsomal PNA separated from mouse liver tissue at various times after the ad- 

 ministration of P32.9' 



2iooor 



^15000- 



9000- 



3000 



MA.^INE 



BIOLOGICAL 



LABORATORY 



LIBRARY 



WOODS MOLE, mzs. 

 W. H. 0. I. 



.L 



96 



10 20 30 40 50 60 

 Time after administration of P" (hr.) 



Fig. 2. Relative specific activities of the cytidylic acids of nuclear PNA, mito- 

 chondrial PXA, and microsomal PNA separated from rabbit liver at various times 

 after the administration of P^^. The points for mitochondrial and microsomal PNA 

 were coincident and the resultant curve has been termed "granules."' 



all agreed on the very much more rapid uptake of P^'- by nuclear than 

 by cytoplasmic PXA at short time intervals after administration of the 

 isotope (Figs. 1 and 2 and Table V Chapter 25). 



The incorporation of radioactive phosphorus into the individual nucleo- 

 tides of nuclear and cytoplas.nic PXA has been studied by Marshak and 

 Vogel,'"" Mclndoe and Davidson, ^^ Davidson et al.,^^ Smellie et al.,^ and 

 by Tyner et al.^^ The results show no major differences between the four 



^00 A. Marshak and H. J. Vogel. /. Cellular Comp. Physiol. 36, 97 (1950). 



