STRUCTURAL COMPOSITION OF THE ALBUMIN*. 39 



led to uniform results. In the case of vitellin, in which the nearest 

 approach to actual conditions has probably been made, Griibler deter- 

 mined the molecular weight as 8848, from which Bunge deduced 

 the formula C^H^Ny/)^. 



That the size of the molecule is very large in all albumins can- 

 not be doubted. Sabanejeff, who recently attempted to determine 

 this for egg-albumin by means of Raoult's method, which is based 

 upon a determination of the lowering of the freezing-point, obtained 

 the figure 15,000. Whether or not this method can be successfully 

 utilized in the determination of the molecular weight of all albumins 

 remains to be seen. 



Structural Composition of the Albumins. Of the structural 

 composition of the albumins little is known that is definite. We 

 have seen in the preceding chapter that in plants the primary syn- 

 thesis of the albumins probably occurs through a union of the 

 radicles of formic aldehyde and of hydrocyanic acid to form chains 

 of the composition 



CO CII 2 .CH 2 CH NH CH 2 CH NH CH 2 COOH, 



and it was pointed out that on hydrolytic decomposition of all albu- 

 mins certain amido-acids, belonging to the fatty acid and the aro- 

 matic series, are constantly obtained. We have evidence, moreover, 

 that a protamin radicle, a carbohydrate group, and certain sulphur 

 groups are present, but of the manner in which these various groups 

 are united with each other, and of their distribution in the albu- 

 minous molecule, we know practically nothing. 



According to Schiitzenberger, all albumins are essentially very 

 complex ureids, or oxamids, in which the urea is united with certain 

 glucoproteins. These latter on hydrolytic decomposition take up 

 water, and form amido-acids of the leucin and leucein series, re- 

 spectively. They may be represented by the general formula? 

 C H H 2n+1 NO 2 and C^H^n^NC^. After decomposition the nitrogen 

 would accordingly be found as amido-nitrogen, while in the albu- 

 minous molecule itself it is supposedly present as imido-nitrogen. 



This theory is based essentially upon the observation that during 

 the decomposition ~of the albumins with superheated baryta-water, 

 carbon dioxide, oxalic acid, and ammonia are formed in the same 

 relative proportions as during the decomposition of urea and 

 oxamid. 



With fibroin Schiitzenberger thus obtained the following complex 

 result : 



C 71 H ]07 N 24 25 + 24H 2 = 5C,H,0 4 -f 1I S CO 8 + 5C 2 H 4 O. 2 

 Fibroin. Oxalic acid. Acetic acid. 



and the mixture of amido-acids yielded 



C68H,4iX0 = C 9 H n NO 3 + 7C 2 H 5 NO 2 -f 7f'JI 2 NO, -f 2C 4 H 9 NO., 4< ' 4 1 1 7 NT> 2 

 Tyrosin. Glycocoll. Alanin. Ainido- Amido-acid 



butyric acid, of the acrylic 



scries. 



