INTERACTION OF PLASMA PnOSTHATP: WITH THE PlIOSPnORVS COMPOUNDS 485 



than 99.9% was removed^^\ A powerful agency pi educing hydrolysis of 

 hexosemonophosphate is Robison's bone enzyme. The presence of 

 small amounts of this enzyme in the plasma was found by Martland 

 and RoBisoN^"^ which according to them is possibly derived from bone 

 by slow diffusion. These small amounts of bone enzymes were presumably 

 responsibh^ for the hydrolysis of hexosemonophosphate in our experiments 

 in vitro, while the much more rapid disappearance of the labelled hexose- 

 monophosphate from the blood in vivo is probably due to the much 

 larger amounts of bone enzyme present in the bones and other organs, 

 especially the kidneys^^\ As seen in Table 7 the specific activity of the 

 corpuscle inorganic P is appreciably lower than that of the plasma 

 inorganic P, while that of the corpuscle ester P is only slightly lower 

 than that of the corpuscle inorganic P. 



Table 7. — Specific Activity ob' P Fractions 1^2 



Hoi'Rs After Administration of Labelled 



Hexosemonophosphate 



Fr;iotii)il 



Specific activity 



Plasma inorganic P . . 



Plasma ester P 



Corpuscles inorganic P 

 Corpuscles ester P . . . . 

 Liver inorganic PC**) . . . 

 Liver ester P 



1 



0.9 



0.3 



0.23 



0.62 



0.22 



(^) A large part of the hexosemonophosphate removed may have been taken 

 up by the tissues. R. T. Bbain, H. O. Kay and P. G. Mabshaxl {loc. cit.) found 

 namely that in the course of 5 min more than three-quarters of the injected 

 glycerophosphate left the human circulation and as in this time it had not been 

 excreted in the urine, nor hydrolysed into inorganic P in the blood, it must have 

 been taken up by the tissue. 



(2) Martland and Robison, Biochem. J. 20, 847 (1926). 



(3) Bodansky [J. Biol. Chem. lis, 391 (1937)] concludes that the phosphatase 

 in question comes from the bone, kidney or some other tissue, but not from the 

 intestinal mucose. 



(4) We were prevented in extracting at once the inorganic and acid soluble 

 organic P of the liver and therefore some of the latter may have been 

 decomposed (comp. E. JaKOBSEN, Biochem. Z. 242. 232, (1931), supplying 

 inorganic P of low activity. The specific activity of the inorganic P present 

 as such in the intact liver may therefore have boon higher than stated 

 above. In this connection it is of interest to know that in the case of a 

 rat, which had been injected with labelled hexosephosphate and killed 2 hours 

 later, no such difference was found. Relative specific activities : Plasma 

 inorganic [)hosj)hate 1.0- li\cr inorganic phosphate 0.97; liver ester O.oS. 



