C 6 H 4 \/CH or C,H 4 \ /CH 



NH 



86 THE CLEAVAGE-PRODUCTS OF THE ALBUMINS. 



Through loss of CO 2 tyrosin yields para-oxyphenyl-ethylamin : 



C 6 H 4 (OH).CH 2 .CH(NH 2 ).COOH == CO 2 + C 6 H 4 (OH).CH 2 .CH 2 .NH 2 

 Tyrosin. Oxyphenyl-ethylamin. 



In a similar manner phenyl-alanin can give rise to pheuyl-ethy- 

 lam in : 



C 6 H 5 .CH 2 .CH.NH 2 .COOH = CO 2 + C 6 H 5 .CH 2 .CH 2 .NH 2 

 Phenyl-alanin. Phenyl-ethylamin. 



Tryptophan (skatol-amino-acetic acid) is the only indol derivative 

 which is formed from the albumins on hydrolysis by means of the 

 common digestive ferments : 



C.CH 2 .CH(NH 2 ).COOH C.CH(NH 2 ).CH 2 .COOH. 



[.<> 



NH 



This can now be regarded as the mother-substance of the aromatic 

 products indol, skatol, and skatol-carbonic acid, which are con- 

 stantly formed from the albumins by putrefactive organisms. In 

 contradistinction to tyrosin and its derivatives these bodies belong 

 to the ortho series. 



Indol, skatol, and skatol-carbonic acid are closely related to each 

 other and to indigo. Skatol thus results from indol through a sub- 

 stitution of the methyl-group for a hydrogen atom of one of the CH 

 groups, as shown by the formula : 



/CH . /C(CH 3 U 



C 6 H 4 / ^CH C 6 H 4 / ^J3CH 



Indol. Skatol. 



Skatol-carbonic acid then results from skatol through a union with 

 carbon dioxide : 



Ce H/^C.COOH 



Skatol-carbonic acid. 



In their passage through the animal body indol and skatol are 

 oxidized to indoxyl and skatoxyl, and are eliminated in the urine to 

 a great extent, in combination with sulphuric acid, as potassium 

 indoxyl sulphate (animal indican) and potassium skatoxyl sulphate, 

 while the skatol-carbonic acid is excreted as such. These changes 

 can be expressed by the equations : 



/CH. /C(OH) 



(i) C 6 H 4 <^ H ^CH + o - ^XNH^- 



Indol. Indoxyl. 



C(O.S0 8 H)< 



/ <v /. 3 



(2) C 6 H 4 <(^ H ^>CH + H 2 S0 4 = C 6 H 4 ^ NH >CH 



Indoxyl. Indican. 



