220 



UNITY AND DIVERSITY IN BIOCHEMISTRY 



J 



NH, 

 I (bacteria) 



•CHs-CH-COOH ^ 



pyridoxalphosphate 



tryptophan 



O 



II 



NH, 



-C-CH,.^CH-COOH 



-N-CH 

 H M 

 O 



(orinylkymirenin 



/\ 



V 



O NH2 



II I 



— C-CH,-CH-COOH 



kvnurcnin 







-C-CHa-CH— COOH 



HO-CH2-CH-COOH + 

 I 

 NHj 



serine 



Af 



V^ 



N 



/ 



O 



II 

 CHj-C-COOH 



indolepyruvic acid 



<^ 



COOH 



NH2 



NH2 

 OH 

 ]-hydroxykynurenin 







anthranilic acid 



OH 



V^N 



^COOH 



COOH 



NH2 



kynurenic acid 



OH 



WAj^^COOH 

 OH 



xanthurenic Bcid 



COOH 



OH 



3 -hydroxy anthranilic acid 



^^ 



quinolinic acid 



indole 



/ 



COOH 

 NH. 



anthranilic acid 



CH,-CH-COOH 



I 

 NH,. 



itaninc 



COOH 



Z' 



N 

 oicotinic acid 



Fig. 53 — Degradation of tryptophan. 



