552 



12. RATES OF INHIBITION 



are integratable but the resultant expressions are unwieldy. However, 

 it is evident that the rate of inhiljition will progressively become even 

 less than the irreversible mutual depletion system and the final equilibrium 

 level of inhibition achieved will be less. 



TIME 



MIN 



Fig. 12-15. Logarithmic plots of inhibition curves in mutual 

 depletion systems. The curves correspond to those in Fig. 12-14. 



Rate of Competitive Inhibition 



When the inhibitor and the substrate compete for the active site on 

 the enzyme, the presence of substrate will reduce the rate at which inhibi- 

 tion occurs, as well as decrease the equilibrium inhibition reached. In 

 such cases, the bound substrate prevents access of the inhibitor to the ac- 

 tive site. Thus only that fraction of the total enzyme concentration that 

 represents the free enzyme will be available for reaction with the inliibi- 

 tor. Of course, the ES complex will dissociate into E and S as the reaction 



