492 



KINETICS OF TRYPSIN DIGESTION 



the 1 per cent gelatin. The difference is greater with the small amount 

 of trypsin than it is with the larger. The same result is shown in 

 Table II in which the change in conductivity after an equal 

 time is given. Here the ratio of the change in the 1 per cent gelatin 

 compared to the change in the 5 per cent gelatin is much smaller 

 when 10 units of trypsin are used than when 1 unit is used. The 

 results when calculated in this way then seem to show that 1 unit of 

 trypsin becomes "saturated" with gelatin .at a lower concentration 



0S> 1.E 1.6 



Time in hours 



Fig. 3. Large scale of the beginning of Fig. 1 . 1 unit trypsin. 



of gelatin than do 10 units. This result, however, is not due to the 

 "saturation" or combination of the enzyme with the gelatin but to 

 the fact that different stages of the reaction are being compared. 

 That this is actually the case is shown in Table III, in which the time 

 required to cause the same amount of hydrolysis is given. In this 

 case the amount of products formed is the same in both solutions 

 {i.e. the stage of the reaction compared is the same) and, as the table 

 shows, the relative velocity of hydrolysis of the 5 per cent gelatin 

 compared to the 1 per cent gelatin is independent of the amount of 



