RESULTS OF ANALYSIS 73 



Albumins and Globulins. 



Albumins contain no glycine, whereas globulins contain this amino 

 acid ; they show no other striking differences. Their differentiation 

 on physical grounds is thus scarcely borne out by analysis, and their 

 interconversion, which has been described, may be possible. 



The most recent results for crystallised egg-albumin by Osborne, 

 Jones and Leavenworth [1909] confirm the earlier ones by Abderhalden 

 and Pregl [1905, 2]. They show that workers in different parts 

 obtain very similar results with Fischer's ester method. The values 

 by Hugounenq and Morel [1906] and by Hugounenq and Galimard 

 [1906] are for coagulated egg-white. 



Chapman and Petrie [1909] determined that egg-white contains 2 '4 

 per cent, of arginine, y2 per cent, of lysine, and 07 per cent, of 

 histidine, data which were required for experimental work on nutrition. 



The comparative data by Abderhalden and Slavu [1909], both of 

 serum albumin and serum globulin, with regard to their content in 

 glycine, tyrosine and glutamic acid would incline one to believe that 

 both the serum albumins and the serum globulins of different origin 

 were of the same composition. They show no very great difference 

 from fibrin. 



The composition of lactalbumin has been determined by Abder- 

 halden and Pribram [1907] and by Osborne, Van Slyke, Leaven- 

 worth and Vinograd [1915]. The very high lysine content of this 

 protein accounts for its value in nutrition. It would appear that 

 the globulin in milk contains glycine, a mixture of the coagulable pro- 

 teins having been analysed by Abderhalden and Hunter [1906, i]. 

 Abderhalden and Schittenhelm [1906] found 1*3 per cent, of tyrosine 

 and I per cent, of glutamic acid in the albumin of human milk. 



Hopkins and Savory's thorough investigation of the Bence-Jones 

 protein [1911], in which they showed that its peculiar physical pro- 

 perties were due to the conditions under which it was examined, and 

 that its chemical composition differed so distinctly from that of the 

 proteoses, brings this protein into the class of coagulable proteins as a 

 globulin. The Bence-Jones protein is characterised chemically by a 

 high content of the aromatic amino acids ; the combined values for 

 phenylalanine and tyrosine are higher than those for any other blood 

 or tissue protein. Both physically and chemically this protein seems 

 to stand in a class by itself. Abderhalden and Rostoski [1905, 2] had 

 previously analysed and examined this protein. Their figures are 

 very similar to those of Hopkins and Savory. 



