366 



7. INHIBITION IN MULTIENZYME SYSTEMS 



colytic system may be compartmentalized in that the ATP formed by the 

 oxidation of glyceraldehyde-3-phosphate may not be immediately available 

 to glucokinase (Chance and Hess, 1959). 



The detailed mechanism of oxidative phosphorylation is not sufficiently 

 understood to represent the various steps accurately, but the following 

 steady-state system will serve to illustrate certain aspects of the behavior. 



El 



A + P -> B + ~P 



~ P + ADP -^ ATP 



E3 

 ATP -> ADP + P 



(7-49) 



B 



Reaction 1 establishes a high energy bond, --^ P, which may involve a 

 group on the enzyme, reaction 2 transfers the high energy phosphate to 

 ADP, and reaction 3 is a means of regenerating ADP so that reaction 2 

 may proceed in a steady state. Reaction 3 may be the splitting of ATP 



02 



i(0T1 E2) 



Fig. 7-33. Effect of noncompetitive inhibition of Eg on the over-all 

 inhibition of a regenerative system (7-39). Curve 1: (B)< = 0.1 mM; 

 curve 2: (B), = 10 mM; curve 3: inhibition of E^ for comparison. 



