24 



IMMUNO-CATALYSIS 



For example, in 0.036m trichloracetic acid the [a]D of menthone 

 was 21.1°, and in 0.762m acid the [a]D was 11.3°. This depression 

 of optical activity was dependent on acid strength; for there was 

 hardly any change in weak acids such as acetic acid, indicating that 

 there was very little complex formation. The inversion of menthone 

 may schematically be represented as follows: 



H 



I 



CH3 — G — CHs 



I 



*C— H 



H2C 

 H2G 



c=o 



CH, 



*C— H 



I 

 CH3 



+ ha; 



+A- 



H 



I 

 GH3 — G — GHs 



H2G 

 H2G 



\ 



G— OH 



+ HA 



GH2 



C— H 



I 

 CH3 



The examples presented here suffice to give a general idea about 

 quite a large class of chemical changes which occur generally accord- 

 ing to the mechanisms underlying the examples cited. 



From the standpoint of the subject matter the most fundamental 

 aspects of these changes are: in the first place, when a chemical 

 change takes place, a new substance is formed; secondly, the change 

 is stoichiometrical, for every a-d-glucose molecule which undergoes 

 mutarotation a molecule of /?-d-glucose is formed; thirdly, these 

 changes are accelerated by catalytic agents, and none of the final iso- 



