J. A. BASSHAM AND M. CALVIN 



energy change would be required for the entire process, so that 

 about 15 kcal./mole might be required for the formation of ATP 

 by such a mechanism. It is thus possible that anywhere from 1 to 

 4 molecules of ATP might be formed for each molecule of primary 



H 



I 



H-0 



Fe 



H 

 I 

 ,0-H 







II _ II 



+ AMP-O-P-0 + HO-P-0" 

 I I 



OH 0" 



Coenzyme 

 and/or protein 



AMP-O-P 

 I 

 



l?/6^ !?/0- 



Fe** 



P-OH 

 1 

 .0 



AMP-O-P *PrOH;-- 



I I 







Fe*** 



Coenzyme 

 and/or protein 



Coenzyme 

 and/or protein 



^v^. 



° n ° 



ll/0\ II 

 AMP-O-P P-0" 



n 



II /0\ II 



AMP-O-P 



~P-0" 



+ e 



Fe*** 



\ 



Fe' 



Coenzyme 

 and/or protein 



2 HgO 



Coenzyme 

 and/or protein 



* 

 ATP 



Fig. 3. A suggested mechanism for ATP formation via oxidation and reduction 



of a metalloenzyme. 



reducing agent used, provided electron carriers of suitable 

 intermediate potentials are available. What these might be is 

 difficult to say, but some cytochromes, for example, cytochrome 

 b, lie intermediate between cytochrome / and TPNH. It is 



60 



