ORIGIN AND MAINTEN. OF OPT. ACTIVITY 41 



ditioii of an enzyme does not change anything either. 

 This does not leave any doubt that, in the case of these 

 isolated enzymatic transformations, we are dealing with 

 true catalysis. 



Finalh% in true catalysis, the optical activity of the sub- 

 stance being formed represents only a temporary phe- 

 nomenon which gradually disappears. This will be clearer 

 when we have examined the dynamics of the two ways in 

 which optical activity could be obtained in biochemical re- 

 actions, namely, the splitting up of racemates and asym- 

 metric synthesis. 



In the splitting of a racemate consisting of two anti- 

 podes, Ai and A^, which change respectively into Bi and 

 B,j, one can represent the process as follows: 



k. 

 k' 



(2) 



If the left initial product Ai is transformed into Bi with 

 a velocity constant A,, different from the constant A-^ with 

 which Aa is transformed into B^, there results optical 

 activity. If Jii = Jici the racemate will be split up sym- 

 metrically. 



In asymmetric synthesis, a symmetric initial substance 

 A is transformed with different velocities, A^^ and k^, into, 

 respectively, Bi and B,„ according to the diagram 



(3) 



A- 

 Kuhn integrated the systems of differential equations 



