550 



CHEMICAL AND PHYSICAL BEHAVIOR OF CASEIN 



monovalent anion H2PO4 and not the trivalent anion PO4. If the 

 same rule holds for casein, the osmotic pressure and viscosity of 

 casein phosphate should be practically identical with that of casein 

 chloride when plotted over the same pH and when_the concentration 

 of (originally isoelectric) casein is the same in both cases (1 gm. in 

 100 cc. of solution). Fig. 2 shows that the osmotic pressure curves 

 for casein chloride and casein phosphate (in 1 per cent^solutions) are 



220 



200 



(^ 160 



d 160 



in 



g 140 

 P, 120 



u 



.r-l 

 -4-> 

 O 



e 

 to 



o 



100 



80 

 60 

 40 



20 

 

 pH 1 2 3 4 



Fig. 2. Osmotic pressure of 1 per cent solutions of casein chloride and casein 

 phosphate as function- of pH. The two curves are ahnost identical. 



almost identical. The curve includes also the osmotic pressure at a 

 pH between 4.0 and 3.0 where the two casein salts are not completely 

 soluble in 1 per cent solutions, but since the relative solubilities of 

 casein chloride and casein phosphate are also practically identical, 

 the osmotic pressure curves for the pH where the solubility of the 

 two salts is not complete remain approximately the same. 



Fig. 3 gives the viscosity curve for 1 per cent solutions of casein 

 chloride and casein phosphate over pH as abscissas. The ordinates 



