THE AMIDO-ACIDS. 89 



acid appears in the urine. The reaction which here takes place may 

 be represented by the equation : 



H 3 C\ /SH 



yC<( + C 6 H 5 Br + CH^ NH 2 ).COOH = 



II, N X COOH Glycocoll. 



Cystein. H 3 C\ /S.C 6 H 4 .Br 



>C< + NH, + 2H 2 



CBL.00.NH/ \COOH 

 Bromophenyl-mercapturic 

 acid. 



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

 ing acids from which they are derived. Glycocoll is thus transformed 

 into acetic acid, leuciu into capronic acid, asparaginic acid into suc- 

 cinic acid, glutaminic acid into glutaric acid, tyrosin into para-oxy- 

 phenyl-propionic acid (hydroparacumaric acid), etc., as shown by 

 the equations : 



CH 2 (NH 2 ).COOH + 2H = CH 3 .COOH + NH 3 

 Glycocoll. Acetic acid. 



/COOH /COOH 



CH 2 .CH(NH 2 ).< + 2H = CH 2 .CH 2 .< + NIL 



\COOH . \COOH 



Asparagiuic acid. Succinic acid. 



/CH /OH 



C 6 H 4 / + 2H = C 6 H 4 < + NH, 



\CH 2 .CH(NH 2 ).COOH X CH 2 .CH 2 .COOH 



Tyrosin. Para-oxy-phenyl-propionic 



acid. 



On oxidation these are further changed into the acids standing 

 next in order in the downward scale. Acetic acid thus gives rise to 

 the formation of formic acid, succinic acid to malonic acid, para-oxy- 

 phenyl-propionic acid to para-oxy-phenyl-acetic acid, etc., as shown 

 by the equations : 



+ CO 2 



H 2 O + CX3 2 



d. 



-OH /OH 



+ 30 = C 6 H/ + H 2 + CX3 2 



\CH 2 .CH 2 .COOH ^CH 2 .COOH 



Para-oxy-phenyl-propionic Para-oxy-phenyl-acetic 



acid. acid. 



Through a splitting off of carbon dioxide para-oxy-phenyl-acetic 

 acid then further gives rise to paracresol, from which phenol is 

 finally obtained on oxidation : 



OH /OH 



= C 6 H 4 < + C0 2 

 CH 2 .COOH X CH 3 



Paracresol. 



/OH 



C 6 H/ + 30 = C 6 H 5 .OH + C0 2 + H 2 O 

 \CH 3 Phenol. 



