6] MUTUAL DISPLACEMENT IN CHROMATOGRAPHY 103 



These experiments demonstrate that protein-protein displacement may be 

 a practically useful phenomenon and that the optimal buffer concentration 

 is an important factor. Sober et al.^ describe how serum, during adsorption 

 on cellulose anion exchanger, separates into a number of 'distinct coloured 

 bands', which, however, are spread out during the gradient elution. Similar 

 observations have been made in Uppsala, especially on calcium phosphate 

 (Hjertén, to be published). The most likely explanation is that a good separa- 

 tion is obtained by mutual protein displacement during the adsorption step, 

 which then is spoiled by the salt gradient which passes over the optimal 

 condition. It may therefore be possible, that in the case of marked displace- 

 ment effects, a better resolution of a chromatogram is obtained with a pro- 

 tein solution as developer [cf. (2)], than that resulting from changes in buffer 

 composition. 



It has been suggested that it is easier to find the optimal conditions for 

 the separation of a protein mixture with zone electrophoresis than with 

 chromatography. Personally I do not want to make any general statement 

 on this question, but I feel that the one-step elution on an anion exchanger 

 is a rapid and convenient way to obtain valuable information about a com- 

 plicated enzyme mixture.^-^-^ 



REFERENCES 



1. A. TiSELius, Arkiv Kemi, 16A, No. 18, 1 (1943). 



2. B. D. POLIS and h. w. shmukler, /. Biol. Chem., 201, 475 (1953). 



3. H. G. BOMAN and L. E. WESTLUND, Arch. Biochem. Biophys., 64, 217 (1956). 



4. H. G. BOMAN and L. E. WESTLUND, Ibid., 70, 572 (1957). 



5. H. A. SOBER, F. J. GUTTER, M. M. WYCKOFF and E. A. PETERSON, /. Am. 



Chem. Soc, 78, 756 (1956). 



6. H. G. BOMAN and u. KALETTA, Biochim. Biophys. Acta, 24, 619 (1957). 



