KINETICS OF PROTEIN HYDROLYSIS 403 



calculated from the monomolecular formula, falls off rather 

 rapidly as digestion proceeds. The decrease in the value of the 

 constant is not attributable wholly to autodestruction of the 

 ferment. Arrhenius has, moreover, shown that Bayliss' results 

 are also in satisfactory accord with the rule of Schtitz. 



Taylor (133), studying the hydrolysis of protamin sulphate 

 by trypsin, found a tolerable accord with the monomolecular 

 law: 



Substrate 0.150. Vol. 100. Ferment 0.001. Temp. 34 degrees, 

 time = 15 30 45 60 75 90 105 150 



k X 10 4 68 69 69 76 66 64 62 60 Average = 67 



Substrate 0.100. Vol. 100. Ferment 0.001. Temp. 34 degrees, 

 time = 15 30 45 60 75 90 105 150 



k X 10 4 79 84 80 76 73 70 64 68 Average = 74 



Substrate 0.0075. Vol. 100. Ferment 0.001. Temp. 34 degrees, 

 time = 15 30 45 60 75 90 105 150 



k X 10 4 90 97 92 88 83 88 79 74 Average = 86 



but it will be observed that the constant rises in value as the 

 substrate-concentration decreases. Therefore, as Taylor points 

 out, in a physical sense the direct proportionality between the 

 velocity of hydrolysis and the concentration of unhydrolysed 

 protein "is only spurious, since it holds but for each particular 

 system." 



On the other hand, Samojlov (116), Walter (148), Sjoquist (125), 

 Schiitz and Huppert (124), Gross (41) and Meyer (79), working 

 with pepsin and employing a variety of substrates, have con- 

 curred in finding that for a considerable period of digestion the 

 Schiitz rule holds good; Borissov (11), employing trypsin. has 

 also confirmed the Schiitz rule and, as we have seen, Arrhenius 

 has shown that the results of Bayliss and of Henri and des Bancels 

 are in accord with this rule. Weis (150) working with the 

 enzyme contained in malt-extract, with wheat-protein as sub- 

 strate, has also confirmed the Schiitz rule, although in very 

 dilute solutions of ferment the exponent of the time tended to 

 rise and approach unity, i.e., the relation tends to become 



x = k s t. (iii) 



Arrhenius (loc. cit.) has shown, from the results of Weis, 

 that the quantity of protein hydrolysed by a given quantity of 



