ii PRIMARY DISSOCIATION-PRODUCTS 21 



great progress has also been made with this class of substances. He 

 first of all set himself the task of preparing, by synthesis, all those 

 decomposition-products of albumins which had not yet been synthetised, 

 and then he worked out a method for the separation of the mono- 

 amino- acids from one another. With the help of his pupils he 

 succeeded : 



1. In obtaining two new amino-acids from albuminous substances, 



namely, a-pyrrolidin-carboxylic acid and oxy-a-pyrrolidin- 

 carboxylic acid. 



2. In demonstrating that alanin, serin, phenylalanin, and amino- 



valerianic acid form more or less constant dissociation-pro- 

 ducts of all the albumins and not merely of a few. 



3. In estimating, at least approximately, the amount of amino- 



acids occurring in different albuminous bodies. 



With the possible exception of tryptophane 1 and some substances 

 isolated by Levene, 2 who finds that the amino-valerianic acid, which 

 is formed during the autolysis or autodigestion of the pancreas and of 

 the liver, has a bitter taste, while all a-amino-acids have a sweet taste, 

 all the dissociation-products of albumins are a-amino-acids, which 

 means the aminogen group, NH 2 , is attached to the first carbon atom 

 next the carboxyl group, COOH. 



NH 2 



I " /> 

 C Cv 

 | X OH 

 H 



This configuration determines the chemical behaviour of amino- 

 acids, and thereby of the whole albumin molecule. All the substances 

 obtainable from albumin by its dissociation with acids or with trypsin 

 are optically active with the exception of glycocoll and serin, while 



Carboxylic Acid,' Ber. d. deutsch. chem. Ges, 35. IIT. 2660 (1902); E. Langstein, 

 ' Hydrolysis of Zein,' Zeitschr. f. physiol. Chem. 37.^508 (1903) ; E. Abderhalden, 

 ' Oxyhsemoglobin,' ibid. 37.^484 (1903); ' Serumalbumin,' ibid. 37.^495 (1903); 

 ' Edestin,' ibid. 37.^499 (1903); ' Cystiudiathesis,' ibid. 38^557 (1903) ; E. Fischer, 

 'Casein and Silk Fibroin,' ibid. 39.^155 (1903); E. Fischer and P. Bergell, *|8- 

 Napthalinsulfoderivates,' Ber. d. deutsch. chem. Ges. 35. III. 3779 (1902) ; E. Fischer 

 and H. Leuchs, ' Synthesis of Serin, of ^-Glucosamic Acid and other Oxyamino Acids,' 

 ibid. 35. III. 3787 (1902) ; 'Synthesis of d-Glucosamin,' ibid. 36. I. 24 (1903); E. 

 Fischer and E. Abderhalden, 'Trypsin Digestion,' Zeitsch. f. physiol. Chem. 39^81 

 (1903) ; E. Fischer, Ber. d. deutsch. chem. Ges. 36. III. 2982 (1903). 



1 See p. 53, under Tryptophane. 

 V 2 Levene, Zeitschr. f. physiol. Chem. 41. 100 (1904). 



