ii UNCLASSIFIED DISSOCIATION-PRODUCTS 83 



1. Amino-butyric Acid, C 4 H 9 N0 2 = CH 3 . CH 2 . CH(NH 2 ). COOH, 



or butalanin. Schiitzenberger l first described it as one of the dissocia- 

 tion-products to be obtained by heating albumins under pressure 

 with barium hydrate. E. Fischer 2 discovered in fibroin and in 

 gelatine, by means of the ester-method, a body which probably was 

 amino-butyric acid, but which could not be identified with certainty ; 

 and Levene 3 found it amongst the dissociation-products of auto- 

 digested testes. 



2. a-Thiolactic Acid, C 3 H 6 S0 2 - CH 3 . CH(OH) . CSOHCS(OH). 

 (Lactic acid is : C 3 H 6 3 " = CH 3 . CH(OH) . COOH). 



a-Thiolactic acid was prepared by Friedmann 4 from horn along 

 with cystin and cy stein. It cannot be regarded as a derivative of 

 horn-cystein, as in the latter the SH group is in the /3 position (compare 

 p. 56 ). Loven 5 prepared synthetically a-thiolactic acid from pyro-uvic 

 acid (propanonic acid) CH 3 CO . COOH (Brenztraubensaure) and /3-thio- 

 lactic acid from /3-iodo-propionic acid. Morner 6 gives characteristic 

 reactions for both acids and also new methods for preparing them 

 in a pure state, and he further states 7 that not only in serum-albumin, 

 serum-globulin, horn, and hair, but also in fibrinogen, egg-albumin, 

 casein, and in the shell-membrane of hens' eggs, the whole of the 

 sulphur is in some form of cystin (see p. 56) and none present as a 

 thiolactic acid. 



3. Pyro-uvic Acid, CH 3 . CO . COOH, or Brenztraubensaure of 

 the Germans, is, according to Morner, 8 a very constant, secondary 

 dissociation-product of proteids. 



4. Diamino-acetic Acid, C 2 H 6 N 2 2 = NH 2 . CH(NH 2 ) . COOH. 

 Drechsel 9 found it along with other bases in casein, but its occurrence 

 is denied by Willstatter 10 and Sorensen, 11 as diamino-acetic acid pre- 

 pared synthetically has quite different properties. 



5. Glucosamin, C 6 H 13 N0 5 (for constitutional formula see p. 158). 



1 M. P. Schiitzenberger, Bull, de la Soc. chim. 23. 161, 193, 216, 242, 385, 433, 

 24. 2, 145 (1875). 



2 E. Fischer and A. Skita, Zeitschr. f. physiol. Chem. 33. 177 (1901) ; E. Fischer, 

 P. A. Levene, and K. H. Aders, ibid. 35. 70 (1902). 



3 P. A. I.evene, Amer. Journ. of Physiology, 11. 437 (1904). 



4 E. Friedmann, Hofmeister 's Beitr. III. 184 (1902). 



5 J. M. Loven, Journ. f. prakt. Chem., N.F., 29. 366 (1884). 



6 K. A. H. Morner, Zeitschr. f. physiol. Chem. 42. 349 (1904). 



7 K. A. H. Morner, ibid. 42. 365 (1904). 



8 K. A. H. Morner, ibid. 42. 121 (1904). 



. 9 E. Drechsel, Ber. d. Sachs. Ges. d. Wissenschaften zu Leipzig, math.-phys.ik. Kl. 

 1892. p. 115. 



10 R. Willstatter, Ber. d. deutsch. chem. Ges. 35. II. 1378 (1902). 



11 S. P. L. Sorensen, Compt. rend, des travaux du Laborat&ire de Carlsberg, 6. 1 

 (1903). 



