BACTERIAL RESPIRATION 



203 



The pyridine ring in co-enzjTue I becomes reduced 

 to give dihydroco -enzyme I which can be re -oxidised, 

 in the presence of the specific flavoprotein acting as a 

 dehydrogenase, to give the original co-enzyme : — 



CH 



CH 



C.CONH, 



II I 



CH CH 



\// 



N 4- 

 HOCH I 



N = C.NHa 



I I 



CH C— No 



N — C— N/' 

 CH- 



CH 



HOCH 



OH 



HOCH 



HOCH 



I 

 CH- 



I I I I 



CHj— 0— P— 0— P— 0— CH2 



II II 







CH 



CH 



II 

 CH 



C.CONHa 

 CHa 



N 



I 

 CH- 



I 

 HOCH 



HOCH 



I 

 CH- 



I 



OH 



-f 2H 

 - 2H 



N= C.NH2 



I I 



CH C— N.\ 



I! II ^ 



II II / 



N— C— N^ 



I 

 CH- 



HOCH 



I 

 I 



CH 



O 



OH 



HOCH 



I 

 CH 



CHo— 0— P— 0— P —0 — CH. 



II II 







The breakdown of formic acid to hydrogen and 



