84 THE CLEAVAGE-PRODUCTS OF THE ALBUMINS. 



isethionic acid, H(C 2 H 4 .OIT)SO 3 , in which the hydroxyl group 

 has been replaced by the amino-radicle : 



CaHuNOjS + H 2 = C 24 H 40 5 + C 2 H 7 N0 3 S 

 Taurocholic Cholalic Taurin. 



acid. acid. 



After the ingestion of amino-acids, moreover, the corresponding 

 compounds of carbamide, CONH, appear in the urine. These are 

 spoken of as the uramic acids, and comprise methyl-hydantoinic acid, 

 taurocarbamic acid, uramino-benzoic acid, and tyrosin-hydantoinic 

 acid, or hydantoin-hydroparacumaric acid. They are found after 

 the ingestion of sarcosin or methyl-glycocoll, of taurin, amino- 

 benzoic acid, and ty rosin, respectively. The syntheses which are 

 thus effected may be represented by the equations : 



C 3 H 7 2 + CONH == C 4 H 8 N 2 3 

 Sarcosin. Methyl-hydantoinic 



acid. 



C 2 H 7 NS0 3 + CONH == C 3 H 8 N 2 SO, 

 Taurin Taurocarbamic 



acid. 



C 7 H 7 NO 2 + CONH = C 8 H 8 N 2 O 3 



Amlnobenzoic Uramino-benzoic 



acid. acid. 



[ U N0 2 -f CONH == C 1? H 10 N 2 3 -f H 2 O 

 rosin. Tyrosin-hydantoinic 



acid. 



The cystin complex of the albuminous molecule is the mother- 

 substance of taurin. On oxidation it is first transformed into cys- 

 teinic, acid and by loss of CO 2 this gives rise to taurin, as repre- 

 sented by the equations : 



(1) CH 2 .S S.CH 2 CH 2 .SO 2 .OH 



CH.NH 2 CH.NH 2 + 5O + H 2 O = 2 CH(NH a ) 



COOH COOH COOH 



Cystin. Cysteinic acid. 



(2) CH 2 .S0 2 .OH 



| CH 2 .S0 2 .OH 



CH(NH 2 ) CO 2 = | 



Cysteinic acid. 



Analogous to the formation of taurocarbaminic acid from taurin 

 cystin gives rise to the formation of cystin hydantoinic acid on treat- 

 ing with cyanic acid : 



On reduction cystin yields cystein : 



CH 2 .S S.CH 2 CH 2 .SH 



I I I 



CH.NH 2 CH.NH 2 -f 2H = 2CH.NH 2 



COOH COOH COOH 



Cystin. Cy stein. 



On reduction the amino-acids are transformed into the correspond- 



