319 



TABLE 16. 



3 g. of Soja on 220 c.c. 



ammonium-carbonate (= 2% urea) 



0.25 «0 urea pH = 1 



t (minutes) 



m 



0,1 log ~ + 0,25 i/ 



110 



0.985 



0.0039 



nc 



These results show clearly, that the formula —loq - -\- 



0,434 • 1 — // 



-\- ay ^= mt represents equally well the course of the reaction in urea 



solutions of far greater concentrations than above in the phosphate 



mixtures. 



The nearly straight line, found generally in the hydrolysis of urea 



by urease, when a is not small, or at any rate large in comparison 



nc 

 with———, is ennally well in accordance with the radialiou theory 

 0,434 ' 



as the logarithmic curve, the ordinary representation of the law of 



mass action, predicted by the same theory for dilute urea solution, 



if c is relatively large. 



Initial velocity of urease action in urea solutions of different 



concentration. 



Using phosphates as buffers it is, as shown above, impossible (o 

 study the course of the reaction in urea solutions, whose concen- 

 tration exceeds about 0,02 "/„. If, however, we allow the same 

 quantity of enzyme to act under the sauie conditions on urea-solutions 

 of different concentration only to such an extent that no more than 

 about 0,02 7o '""ea concentration is hydrolysed, the phosphate mixtures 

 can maintain a constant />// in these initial periods of the process. 



The experiments on this line were all arranged in the following 

 manner : 



