THE pH-FUNCTIONS OF WEAK ACID AND BASES 



651 



(B,) 



(B,) = 



1 + 



1 + 



(H) 



Kg' 



(H) 



+ 



K„ 



(H) 

 K„'K„" 



(H)^ 



(HB) 

 (H3) 



In terms of the pH functions: 



(B,) =A"(B) =A."(HB) =A,,"(H,B) 



(14-7) 

 (14-8) 



(14-9) 



The convention is adopted with respect to these functions that the total 

 number of dissociable protons is represented by the primes and the partic- 

 ular species to which the function applies is given in the subscript. When 

 three or more protons must be taken into account, similar expressions may 

 be formulated. 



The values of the various functions may be summarized here for reference. 

 B may refer to the enzyme active site, the substrate, the inhibitor, or to 

 any of the complexes between them; thus fj/^^ is the function expressing 

 the concentration of HES, the enzyme-substrate complex associated with 

 one proton, when the three forms — ES, HES, and HgES — occur. 



A' 



Jhb 

 h" 

 Jhb 

 fh/ 



A'" 



Jhb 



fh^b' 



Jh^b' 



= 1 + 



= 1 + 



= 1 + 



= 1 + 



= 1 + 



= 1 + 



= 1 + 



= 1 -f 



= 1 + 



(H) 



Kg 



(H) 



(H) 



(H) 

 Kg' 



Kg' 



(H) 

 (H) 



Kg'" 

 Kg'" 



Kg" 



(H) 



Kg' 



(H) 



+ 



+ 



-f 



+ 



+ 



+ 



-f 



(H)^ 



Kg'Kg" 



K" 



(H) 



Kg' Kg" 



(H)^ 



Kg"Kg"' 



(H) ^ 



(H)3 



Kg'Kg"Kg" 



(H)^ 



Kg" 



(H) 



Kg' 

 Kg'K, 



(H)^ 



+ 



Kg'Kg 



Kg" Kg 



+ 



Ka'Kg'Ka'" 



(HF 



(14-10) 

 (14-11) 

 (14-12) 

 (14-13) 

 (14-14) 

 (14-15) 

 (14-16) 

 (14-17) 

 (14-18) 



