68 



UNITY AND DIVERSITY IN BIOCHEMISTRY 



(UTP), a uridine-5 '-diphosphate (UDP) and a uridine-5 '-monophosphate 

 (UMP), exist. 



ATP 



ADP 



AMP 



Adenosine 



Adenine 



N=C— NH2 



HC C— N 



\ 



CH 



N— C— N 



OH OH 



C— C- 



H H 



-C— C— CH2— O- 

 H H 



-P— O- 



II 

 O 



-P— O- 



II 



o 



OH 



I 



-p=o 



I 



OH 



HOC=N 



I I 

 HC C=0 



II I 

 HC— N- 



OH OH 



C— C C— C— CH2— O- 



H H H H 



Uracil 



OH 



I 

 -P— O- 



II 



o 



OH 



I 

 -P— o- 



II 



o 



OH 



I 



-p=o 



I 



OH 



Uridine 



UMP 



UDP 



UTP 



(c) Uridine diphosphate glucose (UDPG) — This nucleotide is the coen- 

 zyme of the isomerase which transforms galactose- 1-P into glucose- 1 -P. 

 It was discovered by Leloir, and has been isolated both from yeast and from 

 animal tissues so that it appears to be of general importance. A whole 



