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ADVENTURES IN RADIOISOTOPE RESEARCH 



As seen in Table 7, the non-acid-soluble ^^P makes out only 35.0 resp. 

 33.8 per cent of the total ^-P present. At least 65 resp. 66.2 per cent 

 of the nucleic acid added was thus decomposed during the experiment. 

 In fact the actual amount of nucleic acid decomposed is larger, as the 

 active non-acid-soluble fraction contains not only the active clesoxy- 

 ribosenucleic acid added but also phosphatides and minute amounts^^^ 



Table 7. — ^^P Content (in Aebitrary Units) of the Different FRAcaioNs in 

 Experiments I and II after Incubation of the Liver Slices in a Bicarbonate 

 Ringer Solution Containing Labelled Desoxyribonucleic Acid for 4 Hours 



AT 37° 



II 



Free ^^P in Ringer-solution 



Acid-soluble ^^P in liver slices 



Total acid soluble ^zp . . 



Nucleic acid ^^p in Ringer solution 



Non-acid-soluble ^^P in liver slices 



Total non-acid soluble ^^P 



Non-acid soluble 32p of all fractions in percentage of the total ^^p 

 content of all fractions 



Percentage of the total acid-soluble ^^p present in Ringer-solution 

 as free ^^P 



3,600 



738 



4,338 



1,950 

 377 



2,327 



35.0 

 83 



3,120 

 810 



3,930 



1,650 

 355 



2,005 



33.8 



79 



cf active desoxyribo- and possibly larger amounts of ribonucleic acid, 

 formed in the liver slices in the course of the experiment from the active 

 phosphate split off from the active desoxyribosenucleic acid added. 

 Even liver slices are thus very effective in splitting off phosphate from 

 nucleic acid. 



It is of interest to remark that the greatest part of the nucleic acid 

 P must have been split off outside the liver cells, presumably on the 

 cell membranes. The greatest part of the free phosphate split off is 

 namely found in the solution. In view of the comparatively high non- 

 active phosphate content of the liver slices the greater part of the free 

 labelled phosphate split off inside the liver cells can be expected to remain 

 inside the cells and not to diffuse into the Ringer solution. In experi- 

 ments in which labelled free phosphate was added to the Ringer solution^^^ 

 19.5 to 25 per cent of the ^sp added was found to have diffused into the 

 liver slices, thus a similar percentage as found in the liver tissue in the 

 above described experiment. 



■1^ L. Ahlstrom, H. Euler and G. Heve.sy, Ark. Kemi, A 21, No. 6 (1945). 



