PRIMARY DISSOCIATION-PRODUCTS 45 



(X NH 9 OHOHH H NH 2 ,0 



V c c c c c c of 



HCT H H H H H H X OH. 

 Suberic acid is COOH(CH 2 ) 6 . COOH. 



19. Diamino-oxy-sebacic Acid, C 10 H 20 N 2 5 



O NHOHH H H H H NH .0 



/ 



R0 / HHHHHHHH OH. 



This acid was obtained by Wohlgemuth on hydrolysing liver-nucleo- 

 proteid. 1 



20. Caseanic Acid, C 9 H 16 N 2 6 . This is a tribasic acid, and 

 probably a diamino-oxy-compound. Its constitution is unknown. 



21. Caseinic Acid, C 12 H 16 N 2 5 . This is a dibasic acid. It 

 occurs in two modifications, of which the active, slightly dextro- 

 rotatory fraction melts at 228, while the other inactive fraction 

 melts at 245. 



22. a-Pyrrolidin-carboxylic Acid, or Prolin, 2 C 5 H 9 N0 2 



H C 



H C 



CH 



CH.COOH 



NH. 



Soon after it had been first described by Willstatter, 3 E. Fischer 4 

 discovered it amongst the dissociation-products of casein, and since 

 then its occurrence has been demonstrated in all proteids examined for 

 its presence. (See tables, pp. 70-75.) According to E. Fischer and 

 Abderhalden 5 it belongs to the anti-group. 6 



The acid occurring normally in albumins is, according to E. Fischer 

 and Dorpinghaus, 7 /-a-pyrrolidin-carboxylic acid, having 



<=-47-6. 



1 J. Wohlgemuth, Ber. d. deutsch. chem. Ges. 37. 4362 (1904). 



2 E. Fischer has abbreviated a-pyrrolidin-carboxylic acid into "prolin." Ibid. 37. 

 2843 (1904). 



3 R. Willstatter, ibid. 33. I. 1160 (1900). 



4 E. Fischer, Zeitschr. f. physiol. Chem. 33. 151 (1901). 



5 E. Fischer, and E. Abderhalden, ibid. 39. 81 (1903). 



6 The evolution of the chemistry of pyrrol compounds during the last twenty-five 

 years has been described by Giacomo Ciamician, Ber. d. deutsch. chem. Ges. 37. 4200 

 (1904). 



7 E. Fischer and T. Dorpinghaus, ibid. 36. 462 (1902). 



