100 THE AMINO ACIDS 



The CO 2 and urea are then synthesized to form urea. 

 This synthesis may occur according to our present 

 views in any active tissue or organ. Taking leucine as 

 a specific example of oxidative deamination we have 

 the reaction following: 



CH CH 



I I 



CH a + O, CH a + CO, + NH, 



CH.NH a COOH 



COOH 



Leucine Isovaleric acid 



It has been shown that under suitable conditions leu- 

 cine, for example, may yield acetone. In order to 

 explain the chemistry of this change it becomes neces- 

 sary to introduce the intervention of a type of acid 

 known as a ketone acid, that is, one possessing the 

 ketone group, C = O. Leucine by oxidative deamina- 

 tion may be changed to a ketone acid. 



CH CH 



by oxidative 



CH a deamination CH, 



becomes 



CH.NH, C = O 



COOH COOH 



Leucine Ketone acid 



