ORIGIN AND MAINTEN. OF OPT. ACTIVITY 43 



optically active state will l)e considerably greater in 

 asymmetric synthesis than in the splitting of racemates. 



The experimental data reported above, concerning the 

 temporary character of optical activity {cf. also Bredig 

 and Fajaiis, 1908; Bredig and Minaeft", 1932; Nordefeldt, 

 1922) are in agreement with. Knhn's calculations. The 

 conclusion to derive from this agreement is that 

 true catalysis occurs in the isolated enzymatic systems 

 considered. 



Furthermore, it should be noticed that asymmetric syn- 

 thesis, which seems to take place in protoplasm rather 

 than dissociation of racemates, is precisely the process 

 which secures a longer duration of the state of optical 

 activity. 



The maintenance of asymmetry in mineral oils is 

 probably to be explained by the extreme slowness of the 

 transformations which take place in them. 



3. Maintenance of Optical Purity by the So-C ailed 

 " Stereo-aiitonomic Substances." If, in enzymatic sys- 

 tems, one has to do with true catalysis, and in true 

 catalysis there is a gradual decrease in optical activity, 

 one might expect that a substance formed in an asym- 

 metric synthesis be optically less pure than the compound 

 from which it originates (Langenbeck and Triem, 1936). 

 Curie's principle, postulating that any asymmetry origin- 

 ates from another asymmetry of the same order would 

 not hold then. So the presence of protoplasmic com- 

 ponents in the form of pure optical isomers for an in- 

 detinitely long time still lacks an explanation. The 

 features which, in the organization of protoplasm, are 

 responsible for the maintenance of optical purity are still 

 to be found. 



Kuhn (1936) showed that, in some cases, the mainten- 

 ance of optical purity in a system, despite the gradual 

 decrease of optical activity in a single synthetic enzymatic 

 process, can be explained by the behavior of some sub- 

 stances that he called "stereo-autonomic." It is knowni 

 that the right nitrile of mandelic acid, when synthesized 



