The Effects of Salts on Haemoglobin 



crystal, the term y' p should be close to unity, and under the same 

 conditions, curves representing the effects of salts on solubilities and 

 on y p should be the same. 



The experimental results available are summarized in Figure 1. 

 The upper curve S gives values for the solubility ratio determined by 

 E. J. Cohn and A. M. Prentiss 3 . The four lower curves give values 

 for log y p (salt effect) calculated by formula 7. These curves may 

 need modification, when more complete data are available, but there 

 seems to be sufficient evidence to justify the conclusion that salts 

 cause large alterations in the term y' p , the activity coefficient of the 

 protein in the solid phase, because the curves for log y p (salt effect) 

 are much lower than the curve for the solubility ratio. 



This conclusion is supported by the observation that there is a net 

 excess of salts in the solid phase, when crystals of haemoglobin are 

 equilibrated with 0-01 molar ammonium phosphates 6 . 



Received September 1948 



REFERENCES 



1 Adair, G. S. Ann. Rev. Biochem. 6 (1937) 186 



2 Cohn, E. J. and Edsall, J. T. Proteins, Amino Acids and Peptides New York 



1943 



3 Joseph, N. R. /. biol. Chem. 126 (1938) 389 



4 Bjerrum, N. Z. phys. Chem. 104 (1923) 406 



5 Adair, G. S. Trans. Far. Soc. 31 (1935) 98 



* — and Adair, M. E. Bio-chem. J. 28(1934)1230 



7 Katz, J. R. Hoppe-Seyl. Z. 95 (1915) 1 



8 Cohn, E. J. and Prentiss, A. M. /. gen. Physiol. 8 (1927) 619 



189 



