66 



BACTERIAL FERMENTATIONS 



from the 8 nitrogen and carbon atom 2 of the imidazole 

 ring of histidine. 8 These results are consistent with the 

 reaction sequence involving formiminoglutamate shown 

 in Fig. 1. 



HC- 



-N 



HC- 



\ 



CH 



-NH 



•NH 3 



G- 



■N 



V 



CH 



-NH 



+2H 2 



COOH 



COOH 



CH— NH— CH=NH CH— NH 2 



H 2 



CH 2 



I 

 CH 2 



CH 2 



I 

 CH 2 



+ HCO— NH 2 



COOH COOH 



Formiminoglutamic acid L-Glutamic acid Formamide 



Fig. I. Conversion of Histidine to Glutamate by 

 Clostridium tetanomorphum. 



The available information indicates that the main dif- 

 ference in the paths of histidine decomposition by CI. teta- 

 nomorphum and Ps. fluorescens probably lies in the reac- 

 tions of formiminoglutamate. Whereas CI. tetanomorphum 

 removes the terminal nitrogen and carbon atoms of the 

 formamidine side chain simultaneously, Ps. fluorescens 

 removes them by successive hydrolytic reactions with formyl 

 glutamate as an intermediate. 



