38 14. EFFECTS OF pH OX ENZYME INHIBITION 



Table 14-1 

 Expressions fob K/ in Terms of Kf for Various Types of Inhibition " 



Inhibition 



Case I: only inhibitor 

 ionizes 



(a) One form of inhi- 

 bitor active (14-46) 



(b) Both forms of inhi- 

 bitor active (14-48) 



Case II: only substrate 

 ionizes — one form is 

 active 



Case HI: both inhibitor 

 and substrate ionize — 

 one form of each active 



Case IV: only enzyme 

 ionizes 



(a) Competitive on ac- 

 tive form HE (14-52) 



(b) Competitive on ac- 

 tive form E (14-56) 



(c) Noncompetitive on 

 active form HE (14-59) 



(d) Noncompetitive on 

 active form E (14-62) 



(e) Inhibition on inac- 

 tive form E (14-56) 



(/) Inhibition on inac- 

 tive form HE (14-68) 



Case V: Enzyme and in- 

 hibitor ionize 



Values of /i/ obtained from plot of 



Type A 



[l/«, - 1/(S)] 



/'JiJhi j^ 

 A ,■ 



Utfi'+ fhi 



(I) 



Type D 1 Type F 



[IM - (I)] [(I)(l - i)li - (S)] 



MJi J hi rr 



A, 



A', \KJf, 



f^iD + ifs- i)A,- 



/,d) ,. ' fi 



fsil) + ifs - 1)/,A', /, 



Ki 



(1) 



A, 



A, 



A^ 



(H) 



A, 



(I) + (Ae'-l)A, 



(I) 



(H) 

 A„ 



A, 



A, 



A„ 



(I) + (fe' - 1)A, 



"(H) 



f/K, 



f'fi J hi j^ 



f'fi'+ fhi 



A, 



fhe Aj- 

 fe'Ki 



A, A, 



A, 

 //A, 



fhe'K-i 



Same as case IV but /,Aj instead of A, 



