30 CHEMISTRY OF THE PROTEIDS CHAP. 



CH 3 CH(OH) COOH, which is identical with the sarcolactic acid 

 found in muscle during rigor mortis and also in the living organism. 1 

 As carbohydrates readily pass into lactic acid, alanin acts also as a 

 connecting link with these. 2 (See also p. 108, under Physiological 

 siderations.) 



Amino-butyric Acid, C 4 H 9 N0 2 

 H HNH 



2 X 



H C C C C v 

 H H H ^OH, 



is, according to Schiitzenberger, in all probability also a primary dis- 

 sociation-product, but it has not been included here, as there is still 

 some doubt (see p. 83). 



3. Amino-valerianic Acid, C 5 H n NO 2 



H H HNH 2 ,0 

 H C C C C C \ 



H H H H ^Ott. 



It was first found by E. Schulze 3 in germinating plants, and later by 

 Kossel 4 in the protamin clupein, which is prepared from the milt of 

 herrings. E. Fischer has been able to demonstrate its presence also 

 in casein, 5 horn, 6 and gelatine, 7 while in all probability it also occurs 

 in fibroin 8 and zein. 9 As this amino-acid greatly resembles leucin in 

 its properties, it is very difficult to demonstrate its existence in the 

 presence of leucin, as the latter is met with always in much larger 

 quantities. E. Fischer for this reason has not as yet been able to obtain 

 it in such purity as to be able to characterise it more definitely and to 

 identify it with one of the different amino-valerianic acids prepared by 

 him and Slimmer. 10 He believes it to be, however, a-amino-valerianic 



is optically inactive, being composed of dextro- and Isevo -rotatory lactic acids, while the 

 lactic acid found in meat is dextro-rotatory, and has been called sarcolactic acid by 

 Liebig. This a-oxy-propiouic acid, when oxidised yields acetic acid and carbonic acid. 



The /3-oxy-propbnic acid contains no asymmetric carbon atom, and is thei-efore 

 optically inert. On oxidation it yields oxalic acid and carbonic acid. 



1 E. Fischer and A. Skita, ibid. 33."l77 (1901), 



2 E. Fischer and Abderhalden, ibid. 36. 268 (1902). 



3 E. Schulze, Zeitschr.f.physiol. Chem. 17- 193 (1892), 28. 465 (1899). 



4 A. Kossel, ibid. 26. 588 (1899). 



5 E. Fischer, ibid. 33^151 (1901). 



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



7 E. Fischer, P. A. Levene, and R. H. Aders, ibid. 35. 70 (1902). 



8 E. Fischer and A. Skita, ibid. 33*177 (1901). 



9 L. Langstein, ibid. 37. 508 (1903). 



10 M. D. Slimmer, Ber. d. deutsch. chem. Ges. 35. I. 400 (1902). 



