100 THE AMINO ACIDS 



The CO 2 andstsstft-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 8 CH 8 



CH CH 



I I 



CH a + O a CH 3 + C0 3 + NH 3 



CH.NH a COOH 



I 

 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 3 CH, CH 8 CH S 



CH CH 



by oxidative 



CH a deamination CH a 



becomes 



CH.NH a C = O 



I I 



COOH COOH 



Leucine Ketone acid 



