416 



8. INHIBITOR DISTRIBUTION IN LIVING ORGANISMS 



ment due to an enzymic reaction would be relatively slight unless (I,) at- 

 tained near-saturating concentrations, which must be uncommon. The 

 curve for an enzymic reaction was obtained by integration of the Michaehs- 

 Menten equation, from which: 



[(Do - (I)] - 2.3^„, log (I)/(I)o = VJ 



(8-13) 



TIME 



Fig. 8-3. Variation of intracellular inhibitor concentration and inhibition with time 

 (Eq. 8-5). It is assumed that k^ = A_i = A'a- Equations 8-8 and 8-9 then take the 

 following forms when {1^)^ = 10 m3I and the k's are unity: 



(IJ = 7.24 (0..382e-2-6i8« + e-o.382<) 

 (I,) = 4.47 (e-o-382i _ e-2.6i8() 

 The inhibition is assumed to be noncompetitive with K^ — 2 mM. 



A situation of even more common occurrence in the administration of 

 inhibitors to animals may be represented as: 



L 



^•i 



I, 



X 



(8-14) 



where Y designates excretion from the blood stream through the kidney: the 

 inhibitor introduced into the circulation can thus either enter the tissues 



