62 



3. KINETICS OF ENZYME INHIBITION 



and the dependence of inhibition on the constants a and /? is iUustrated in 

 Figs. 3-6 to 3-8. It is readily seen that the kinetic behavior is different in 

 each type of inhibition. In Fig. 3-6 it may be observed that as a becomes 



Fig. 3-3. Variation of the rate with inhibitor concentration for different types of 

 inhibition, pi is — log (I) when (I) is M. A',== 1 mM, Z, =0.1 mil, iC/ = 0.1 mTl/, 

 (S) = 3 mM, and V^ = 100. Curve 1: uninhibited; curve II: competitive inhi- 

 bition; curve III: noncompetitive inhibition; curve IV: coupling inhibition. 



Fig. 3-4. Variation of the fractional inhibition with inhibitor concentration for 

 different types of inhibition. Constants and curve designations as in Fig. 3-3. 



larger, the inhibition approaches a constant level, whatever the value of 

 /5; when cc is infinity the inhibition is completely competitive. It is interest- 

 ing, however, that a must reach fairly high values, that is the substrate bind- 



