502 



ADVENTURES IN RADIOISOTOPE RESEAEC^H 



as much free Pas 1 gm of plasma'^\ This concKision is born out by the 

 experiment. 



The process of incorporation of ^^P into organic phosphorus compounds 

 can be studied in blood hemolysate free from permeabihty considerations. 

 We hemolysed rabbit corpuscles by repeatedly cooling rabbit blood to 

 liquid air temperature. The hemolysate was shaken for 2 hours at 37"= 

 with labelled phosphale of negligible weight. From the trichloroacetic 

 filtrate, the inorganic P present as such in the hemolysate was pre- 

 cipitated as magnesium salt, the filtrate was then made 1 n H2SO4 

 and kept at 100° for 7 minutes. By this procedure, the labile P of the 

 adenosintriphosphoric acid is split off. By a similar procedure, other 

 P fractions were also secured. The results of these experiments are seen 

 in Table 7. 



Table 7. — Specific Activity of the P Fractions of Rabbit 

 Blood Hemolysate Kept for 2 Hours at 37° 



Fraction 



P content 

 in mgm 



Percentage 



disti'ibution 



of "P 



Specific 

 activity 



Inorganic P • • • 



Hydrolysed 0—7 min 



Hydrolysed 7—100 min. ... 

 Hydrolysed 7 min. — 17 hours 

 Residual acid soluble P . . . . 

 Total organic acid soluble P . 



100 

 23.5 



5.8 

 2.58 

 1.07 

 6.29 



In an other experiment the pyrophosphate fraction had a higher 

 specific activity (41). 



All acid soluble organic P fractions secured from the hemolysate were 

 found to contain ^2?, phosphorylation is thus occurring in the blood hemo- 

 lysate. The percentage of adenosintriphosphate, which is resynthesized 

 in the hemolysate, is, however, smaller than the percentage resynthesized 

 in the corpuscles during the same time. In the experiment with intact 

 corpuscles, in the course of IV2 hours, the pyrophosphate P present in 

 the corpuscles had nearly the same activity as the inorganic P present 

 in the corpuscles. In the hemolysate, in the course of 2 hours, the activity 

 of the pyrophosphate P amounted to only about l^ to 1/2 of the activity 

 of the inorganic P. In fact, the difference between the result obtained 

 in the corpuscles and the hemolysate is even larger than stated above. 



(') We can expect 



Cl^rp. H,0 ^ (g X H2POr)corp.H,0 + {h yHPOT^) Corp. H,0 



Cl-pi. H,o (o X HP2d-)pi. H,o + {h VHPO- -)pi H,o 



where a denotes the fraction of phosphate being present as primary ion arid 6 

 the fraction of phosphate being piesent as secondary ion. 



