[Reprinted from the Journal of Physiology. 

 Vol. XX XIII. No. 6, 1906.] 



THE SEPARATION OF PHOSPHORUS FROM CASEIN- 

 OGEN BY THE ACTION OF ENZYMES AND 

 ALKALI. BY R. H. ADERS PLIMMER AND W. M. 

 BAYLISS. (Two Figures in Text.) 



(From the Plujsiological Laboratory, University College, London.) 



IT was found by Bayliss' 1 ' in his experiments on the kinetics of tryptic 

 action, that the great increase of electrical conductivity in the initial 

 stages of a caseinogen-trypsin and a gelatine-trypsin digestion could 

 not be accounted for by the decrease of internal friction, but was in all 

 probability due to a separation of electrolytes from the substances 

 themselves. In the case of caseinogen, however, the increase of electrical 

 conductivity would be partially derived from the separation of its 

 phosphorus as inorganic phosphates. It was with the object of deter- 

 mining the rate at which this latter process took place under the action 

 of trypsin, and comparing these results with those obtained by the 

 electrical conductivity method, that the following experiments were 

 commenced. 



Before the commencement of our researches only two experiments 

 had been carried out on the separation of phosphorus from caseinogen 

 by the action of trypsin. In 1895, Sebelien (2) found that caseinogen, 

 except for a negligible residue, was completely digested, but he made no 

 investigations with regard to the nature of the phosphorus which had 

 gone into solution. In 1898, Biffi< 8) , a pupil of Salkowski, made much 

 more detailed experiments; he also found that, except for a minute 

 residue, in all probability derived from the trypsin employed, the whole 

 of the phosphorus passed into solution ; of this, only about 27 per cent, 

 was precipitated by magnesia mixture, and consequently consisted of 

 inorganic phosphoric acid, the remainder being contained in an organic 

 form. 



We have also determined at what rate the phosphorus of caseinogen 

 is converted into a soluble form under the action of pepsin. A great 

 many more investigations have been made upon this subject than upon 

 PH. xxxiu. 29 



