THE DJAMINO-ACIDS. 89 



ganate Zickgraf obtained hydrocyanic acid, oxalic acid, normal 

 glutaric acid (COOH.CH 2 .CH 2 .CH 2 .COOH), and probably also 

 glutaminic acid. When exposed to the influence of putrefactive 

 organisms it gives rise to the formation of cadaverin penta-methy- 

 lene-diamin a ptomain whicli is frequently found together with 

 putrescin in putrefying albuminous material, and, like this, may 

 also appear in the urine in association with cystin. Its formation 

 is analagous to that of putrescin from ornithin, and may be repre- 

 sented by the equation : 



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



Lysin. CO 3 + CH 2 (NH 2 ).CH 2 .CH 2 .CH 2 .CH 2 (NH 2 ) 



Cadaverin. 



In this manner albumins can give rise to the formation of pyridins, 

 and, as a matter of fact, piperidin results during the dry distillation 

 of cadaverin, as represented by the equation : 



CH 2 CH 2 



CH 2 (NH 2 ).CH 2 .CH 2 .CH 2 .CH 2 (NH 2 ) = CH 2 NH + NH 8 . 



CH 2 CH 2 



On treating lysin with benzoyl chloride Drechsel obtained a 

 body, of the formula C 6 H 12 (COC 6 H 5 ) 2 N 2 O 2 , which he termed lysuric 

 acid, and which is thus homologous with the dibenzoyl derivative 

 of ornithin, C 5 H 10 (COC 6 H 5 ) 2 N 2 O 2 , ornithuric acid. 



An inactive lysin has been obtained synthetically from f-cyan- 



propyl-malonyl ether (NC.(CH 2 ) 3 .CH<^ 2 ^ 5 J, over a-oximido- 



^-cyan-valerianic ethyl ether (NC.(CH 2 ) 3 .C<^ H5 | On racemi- 



sation this was shown to be identical with the active lysin. 



Diamino-trioxydodecanic Acid (C 12 H 26 N 2 O 5 ). As has been 

 pointed out above, this acid has thus far only been obtained from 

 casein ; but there is reason to think that it or similar products may 

 also be contained in other proteins. Its constitution has not yet 

 been established. . 



Histidin. Histidin is formed in very small amounts only during 

 the decomposition of proteins and may be absent. ^ It was long 

 regarded as a diamino-acid, but is now viewed as a-amino-/3-umdazol 

 propionic acid, and is probably represented by the formula : 



CH N 



L 



CH 2 



CH.NH, 



COOH 



