ACTION ON RESPIRATION AND GLYCOLYSIS 83 



be mentioned later, we may proceed to examine the action 

 of drugs on the respiration and glycolysis of muscle. 



Fig. 17 gives a rough outline of the main steps involv- 

 ing the use of oxygen and glucose by muscle. Also in- 

 cluded are the probable points of action of carbon mon- 



co^ 



HCN) 

 A/3 J 



0? ^ 



Cytochrome oxidase\ 



Glucose 



Mustard 90s 

 Lewisite 



^ 



Cytochrome 



Dehydro^nase. 



Pyocyanm 



Glucose phosphate 



Glucose diphosphate 



Olyceraldehyde 



Urethan 



lodoacefate 



Lewisite 



¥ 



Phosphoglyceraldehyde -^ ^HCN 



Diphosphoglyceric acid 



I -E!l 



Pyruvate 



Pyruvic oxidase^* 



Mustard gas 

 Lewisite 

 Vitamin B 



CO2 etc. 

 Fig. 17. A condensed scheme of the enzyme-catalysed steps in the res- 

 piration and glycolysis of muscle, with the points of action of some drugs 



oxide, hydrocyanic acid, azide, urethan, iodoacetate, 

 lewisite, mustard gas, glyceraldehyde, arsenic acid, 

 fluoride and vitamin B^. As is indicated in the figure, 

 we have strong reasons for believing that the enzyme 

 systems concerned in respiration and glycolysis are 

 organised to give rise to a chain of reactions in which 

 each reaction produces a reaction product which is the 

 substrate for the subsequent reaction. As is indicated 



Cell Physiology 6 



