1130 



As /«had appeared to be a function of /J/z with a distinct maximum, 

 the Ph of this maximum would offer the advantage, that here a small 

 variation of pn would produce smaller change in m than elsewhere. 



Secondly, to check the influence of the inavoidable experimental 



errors, the coefficient — — should not be much larger or smaller 



0,434 



than a. For, if the coefficient of log ~— predominates largely, the 



reaction practically corresponds to the ordinary logarithmic line of 

 the law of mass action. On the other hand, a being much larger, 

 a nearly straight line will appear. 



Therefore in these basal experiments a niixture of Na,HPO< 2 aq 

 and KHjPO^ was used in such proportion, that the enzyme-action 

 would proceed in an 8 7o phosphate mixture of about pff=7.ö. 



The materials used w^ere the following: 



Ordinarj yellow (probably Mantchourian) Soja-beans were pow^- 

 dered in a small American "Enterprise" mill, slowly turning the 

 handle to avoid the heating by friction, which is otherwise soon 

 perceptible. The powder was kept in a common stoppered bottle in 

 the dark. 



The KH, PC, and Na, HPO, 2 aq were the purest compounds from 

 Kahlbaum, labelled "zu Enzym-studien nach Sörensen". 



The urea, from Kahlbaum, was recrystallised by the author from 

 alcohol of 96 ° „. 



All experiments in this research were made at a temperature of 

 27° C. This temperature is just high enough to allow without diffi- 

 culty the use of a waterbath of constant temperature nearly the 

 whole year round, and, on the other hand, low enough to avoid 

 the deteriorating effect of higher temperatures on enzyme activity, 

 within reasonable limits of time and true reaction. 



7.28 g. of Na,HPO, 2 aq and 2 32 g. of KH,PO, were dissolved 

 in a stoppered flask to 100 c.c. 



Into this solution 0.4 gram of Soja-meal was introduced, the flask 

 was shaken thoroughly and left in the waterbath of 27° for one 

 hour. After addition of 0.4 gram of kiezelgur, which had been 

 repeatedly washed and then dried, the extract was filtered off easily 

 and perfectly clear through an ordinary pleated filter. In the mean 

 time there had been prepared a solution of 14.4 grams ofNajHPO^ 

 2 aq in 150 c.c. of water in a larger stoppered flask. To this w^ere 

 now added 75 c.c. of the clear Soja extract, by which a diluted, 

 still perfectly clear, extract resulted, which will be indicated by the 

 letter E. 



