PERCENTAGE-COMPOSITION 



65 



The Quantitative Composition of Albumins 



When estimating the percentage-amounts of the different disso- 

 ciation-products found in individual albumins, we must exclude 

 all substances which are formed secondarily. Of the substances 

 enumerated in the list on p. 27 we may assume that they are pre- 

 formed in the albumin-molecule. 



As to whether this list includes all the substances existing 

 primarily in the albumin-molecule cannot be decided as yet, because 

 up till now none of the higher albumins has been dissociated 

 quantitatively. We cannot account for more than 72 per cent of 

 globin, 73 percent of fibroin, and 58 per cent of edestin, while Kossel 

 and Dakin 1 can account for the whole of the protamin salmin. 



The composition of the protamins, which Kossel 1 regards as the 

 simplest albumins, has been put into tabular form by him. 



TABLE SHOWING THE COMPOSITION OF THE PROTAMINS 



The ordinary albumins differ from the protamins simply in possess- 

 ing larger accumulations of mono-amino-acids. Substances, such as 

 leucin, tyrosin, alanin, serin, and diamino-caproic acids, which occur only 

 sporadically in the protamins, are always present in albumins, which 

 in itself renders the albumin molecule more complex than a protamin. 

 This complexity becomes, however, still greater by acids occurring in 

 the albumin, which are altogether absent in the protamins, namely, 

 the dibasic amino-acids : glutaminic acid and aspartic acid. 



1 Paper read at Brit. Ass. for Adv. of Science, Cambridge, 1904, and in Berliner 

 MI'H. Wochensch. No. 41, Oct. 1904, p. 1065 ; also in Zeitschr. f. physiol. Chem. 44. 

 342 (1905). 



