402 ADVENTURES IN RADIOISOTOPE RESEARCH 



Comments on papers 36 — 38 



In oo operation with Parnas (1938) in in vitro experiments, the incorporation of 

 the phosphate group into various acid-soluble phosphoiiis compounds was studied. 

 It was found that a phosphate group may be transferred fiom one organic molecule 

 to another without passing the inorganic stage. For example, when glucose-1 

 phosphoric acid (Cori ester) is transformed in the presence of muscle extract and 

 labelled inorganic phosphate into glucose- 6-phosphoric acid (Robison ester) the 

 esters do not become labelled. 



Simultaniously Meyerhof, et al. studied the rate of interchange between 

 inorganic and pyrophosphate P in muscle-extract and found that after the lapse 

 of 20 sec, a 47 per cent interchange took already place. 



The first in vivo studies on the turnover of acid-soluble phosphorus compounds 

 of the muscle tissue were carried out with frogs (paper 36). The turnover rate 

 of the acid-soluble constituents was found to be influenced to a much higher 

 degree by temperature- changes than by the foimation of the labelled bone apatite 

 crystals. When investigating the rate of renewal of the acid-soluble organic phos- 

 phorus compounds of the rabbit (paper 37), the inorganic phosphate content of the 

 plasma was kept at an almost constant level throughout the experiment, which 

 took 50 days. This made it possible to arrive, by comparison of the specific activ- 

 ities of the cellular inorganic P and the organic P at the end of the experiment, 

 at a renewal figuie of the latter. In experiments of 50 days duration, the results 

 can be expected not to be influenced much by the participation of slowlj^-formed 

 intermediary products, or the specific activity of extracellular phosphate much 

 to differ from that of the intracellular one, in contrast with experiments taking 

 a few hours only. 



Recently in ^^O of Hg^^O a very suitable indicator in the study of the turnover 

 of phosphorus compounds of the muscle cells was found by Fleckenstein et al. 



References 



G. Hevesy, T. Baranowski, A. J. Gutke, P. Ostern and J. K. Parnas (1938) 



Acta Biol. Exp. 12, 34. 

 O. Meyerhof, P. Ohlmeyer, W. Gentner and H. Maier-Leibnitz (1938) 



Biochem. Z. 298, 396. 

 J. Sachs, Isotonic Tracer in Biochemistry and Physiology , New York, 1953. 



A. Fleckenstein, E. Gerlach, I. Janke and P. Marmier, Z. Physiol. C/iem.( 1960) 

 271, 75. 



