CH 2 OH 

 CHNHCO C 6 H e 



COOH 



Benzoylserin 



PoS, 



CYSTINURIA 

 CH 2 SH 



-> CHNH COC 9 H F 



521 



HC1 



CH 9 SH 



CHKEL 



COOH 



Benzoylcystein 



COOH 



CH 2 S S CH 2 



CHNH 9 CHNH, 



COOH COOH 



Cystin 



Four years later Fischer and Raske synthesized cystin from the methyl 

 ester of 1-serin. From this they obtained by the action of phosphorous 

 penta-chlorid and then by hydrolysis with hydrochloric acid 1-a-amino- 

 (5-chloropropionic acid. By treating this with barium hydrosulphid, 

 cystein was produced which when oxidized by a current of air yielded 

 cystin : 



CH 9 OH 



CHNH 



COOCH 3 

 Methyl ester 

 of serin 



CH 2 O 

 PC1 5 



CHNH 2 



HO | 



COOH 



a-amino (3-chlor- 

 propionic acid 



Ba(SH), 



CH 2 SH CH 2 S SCH 2 



CHNH 9 CHNH, 



COOH COOH COOH 



Cystein Cystin 



Of the identity of the cystin obtained from stones and cystin from 

 protein decomposition, we need only mention the work of Fischer and 

 Suzuki, who demonstrated the identity of hair cystin and stone cystin, 

 and of Abderhalden, who compared protein cystin and stone cystin. 

 Fischer and Suzuki found the rotation of hair cystin as 221.9 and of 

 stone cystin 223.6. Abderhalden found the following figures for the 

 rotation of cystin: 



Hair cystin a 20 = -223.8 



Hemp edestin cystin = 218.8 



Feather cystin = 219.8 



Horn cystin = -220.5 



Serum globulin cystin = 221.2 



Serum albumin cystin = 216.8 



That bacteria play an important role in the decomposition of cystin 

 has been demonstrated in a number of instances. Herter, and later 

 Goodridge, showed that upon growing the Bacillus putrificus, the Bacillus 



