ACTION OF ENZYMES 61 



which on integration yields 



_ 1 x(2a-x) . 



k = 2t ' a 2 (a - x? ' 



and very similar equations can be evolved for equations of a higher 

 order. 1 



EXPERIMENTAL OBSERVATIONS ON VELOCITY OF REACTION 

 INDUCED BY ENZYMES 



We may now pass on to the examination of the experimental 

 results on chemical kinetics, and to the investigation of the extent 

 to which such observations are in accord with the equations 

 theoretically deduced above. 



At the outset we are met by great apparent divergence of 

 experimental results, and different statements by different ob- 

 servers. More recent work has, however, tended to show that 

 the apparent discrepancies are due to different observers having 

 worked at different portions of the reaction, that there are several 

 different factors involved which disturb the velocity of the reaction 

 when there is not due attention given to the relative amounts of 

 catalyst and the substratum on which it acts, or to the conditions 

 obtaining at the extreme ends of the reaction. 



In the case of the enzymes it has recently been shown, parti- 

 cularly by the researches of Horace Brown and Grlendinning and 

 of E. F. Armstrong, that the simple logarithmic law deduced 

 above holds only at some distance from the beginning or end of 

 the reaction, and when there is a due proportionality between 

 ferment and substratum. 



The experiments on velocity of reaction may be divided into : 

 (1) those in which, with a constant amount of catalyst throughout 

 the experiment, the course of the reaction is followed from the 

 initial point at which only the substratum or substance upon 



1 For an n-molecular equation the equation of velocity is 



which yields on integration 

 k = 



(-l)t 



