MODES OF LINKAGE BY COVALENT BONDS 



69 



series of compounds exists, with structures similar to UDPG, in which the 

 glucose is replaced by other substances such as acetylglucosamine, for 

 example. 



HOC=N 



HC C=0 



HC— N 



CH.,OH 



HC 



HCOH 



HC 



HCOH 



O 



o 



HCOH 



HC 



CH2 



o — 



HOCH 



OH 



I 

 -P- 



O 



OH 



I 



i 



-P- 



HCOH 



I 

 HC 



— O 



o 



UDPG 



O 



{d) Flavin monophosphate — This is commonly called flavin mononucleo- 

 tide (FMN) but this is incorrect since it is a compound of phosphoric acid 

 with riboflavin which is not a true nucleotide. The phosphate is attached 

 at the 5' position of the ribityl residue. Flavin mononucleotide is the 

 coenzyme of L-amino oxidase and of the TPNH-^Og transhydrogenase. 



OH OH OH o 



III I 



CH2-C-C-C-CH2-O-P-OH 



III I 



H H H OH 



H3C 

 H3C 



v ^=o 



^ 



N 



NH 



O 



