MITOCHONDRIAL STRUCTURE AND FUNCTION 



«7 



Fig. 3. Heavy mitdchundrial traction after freezing and tiiawing. X 4<'>"0o. 



The electron transport particle couples the oxidation of DPNH or succinate 

 to synthesis of ATP but has lost the capacity for carrying out all the oxidative 

 steps of the citric acid cycle. This loss can be correlated with the release of 

 pyridinoproteins and bound diphosphopyridine nucleotide (DPN) during frag- 

 mentation by sonication (25). 



To enable you to visualize a little better just which part of the enzymatic 

 machinery is lost in the transition from mitochondria to ETP, I have made a 

 schematic representation of the electron transfer chain of the two respective par- 

 ticles (fig. 5). Electrons in the mitochondrion originate front the citric cycle sub- 



4 







■^^■- 



»a^. 





%, u 



■-^Vi 



$■ •> 



i' 



>.. 



Fig. 4. Phosphorylating particles tlerived truiii sonicateil heavy niitochoiulrial fraction 

 (ETP„). X 38,000. 



