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UNITY AND DIVERSITY IN BIOCHEMISTRY 



HN CO 



I I H 

 OC C N 



/ 

 HN C NH 



CO 



uric acid 



{uricase) 



I 

 HjN 



I O H 



OC C — N 



HN— C N 



/ 



CO 



H H 



allantoine 



I. 

 (allantoinase) 



I 

 HgN NH2 



I I 



OC COOH CO 



I I I 



HN— C NH 



H 



allantoic acid 



i . 

 (allantoicase) 



COOH NHj 



/ +20=C 



NH, 



H 



Urea 



I 

 (urease) 



I 

 2NH3 + CO2 



Ammonia 



Fig. 91 — The uricolytic enzyme system. 



