92 



iC. Kaziro and K. Tsushima 



2 3 



Haem added, xlO M 



Fig. 10. Effect of pH on the affinity of cytochrome c for added haem. Cyto- 

 chrome c concentration: 3-3 x lO"® m. pH for I, 14-0; II, 13-3; III, 12-57; 

 IV, 12-05; V, 11-8; VI, 11-3. The broken line indicates the concentration curve 

 of alkali-denatured globin haemochrome. 



% 50 



pH 



Fig. 1 1 . pH dependence of the affinity of cytochrome c for added haem. Haem 



was added at each pH and the extinction was read (•). Haem was added to 



alkali-denatured cytochrome c at pH 13-3, and the extinction read at each pH (A). 



The sigmoid curve is for a first order reaction having a pAT value of 120. 



