VARIATION OF ENZYME INHIBITION WITH pH 



685 



curves indicates an ionizing group on the enzyme-substrate complex. In 

 the piiL/-pH plots this is not necessarily so: ionization of the enzyme- 

 inhibitor complex does give an inflection that is concave upwards (num- 

 bers 3, 4, 15, and 16) but other situations (numbers 5, 6, 7, 8, 10, 11, and 

 12) also give rise to such inflections. Therefore, an inflection that is concave 



P^ 



P'K- or fpK- 



PH-^ 



PH-^ 



pK; 



PK; 



hs hei 



PH- 



pK; 



P^a. 



:^K: 





PH-^ 



PH-^ 



pK; 



Pt^i 



8 pKa- ^ 



PH- 



PH-^ 



Fig. 14-10. The pZ/— pH plots for the K/ vahies shown in Table 14-1 to illustrate 



the interpretation of the inflections when K/ is determined from three different 



types of plotting procedures. 



