270 ORIGIN OF STRUCTURES AND FUNCTIONS 



in the Krebs cycle, cytochrome oxidase and also other oxidis- 

 ing enzymes such as succinic, lactic and glycerophosphate 

 dehydrogenases.^^ 



I K 

 mOr HO 



159 



mo 



woo 



^ 



^ 



§ 



^ 800 



dOO 



I 400 



ZOO 



J. 



X 



J. 



Fig. 



OM 0J4 0,64 0,54 0,44 Q34 024 



SUCROSE M 

 21. The respiration of the protoplasts of 



Micrococcus lysodeikticus and the uptake of 

 labelled glycine. 



The enzymes in the mitochondria are not arranged at 

 random but stand in a definite spatial relationship to one 

 another, which is associated with a very precise internal 

 structure of the mitochondria. This reduces the path which 

 must be followed by the substrate or coenzyme to a minimum, 

 which allows a considerable speeding up of long chains of 

 reactions such as the citric acid cycle. K. Lang^^" showed 

 that anything which destroys the structure of the mito- 

 chondria inactivates the so-called cyclophorase system of 

 enzymes discovered in the mitochondria by D. E. Green and 

 his colleagues.^" 



