438 CHEMISTRY OF THE LEUCOMAINS.. 



between ornithin and the ptomain putrescin and the possibility of 

 the latter being formed by splitting off carbonic acid. Although 

 they had in mind experiments in this direction yet nothing was 

 done until Ellinger * effected the transformation. On decomposing 

 ornithin by the aid of bacteria, especially in the absence of oxygen, 

 he obtained putrescin and thus not only furnished a correct explana- 

 tion of the origin of this ptomain but also confirmed the position of 

 the amido groups in ornithin and hence in arginin. The cleavage of 

 proteids by bacteria therefore can be traced through arginin and 

 ornithin to putrescin. The structural relation of these bodies can 

 be seen from the equation : 



NHj.CHj.CHj.CHj.CH(NHj).COOH = NHj.CHj.CH,.CHj.CH,.NHj + CO,. 

 Obnithin. Fdtbescih. 



From this it is evident that ornithin is a-8 diamido valerianic 

 acid and is the next lower homologue of lysin (see p. 444). This 

 diamido valerianic acid in the inactive or racemic form has been 

 recently synthesized by Fischer.^ Like ornithin it has a strong 

 alkaline reaction and gives a white precipitate with mercuric 

 chlorid ; with phosphotungstic acid it yields a heavy crystalline pre- 

 cipitate which can be recrystallized from hot water in colorless 

 needles. With benzoyl chlorid it forms monobenzoyl and di-benzoyl 

 derivatives corresponding to those of ornithin. While Fischer found 

 the natural ornithuric acid to be dextro-rotatory, the synthetic one 

 was inactive, otherwise the two showed the greatest resemblance. 

 The synthetic ornithuric acid melts at 184-185° whereas the natural 

 acid melts at 182° (Jaffd) ; 184° (Schulze and Winterstein). Both 

 yield the characteristic calcium salt. The d-amido valerianic which 

 Salkowski isolated from putrefying proteids in all likelihood is 

 derived from the former. 



On oxidation with potassium permanganate arginin is destroyed 

 but by employing the barium salt Benech and Kutscher ' succeeded 

 in oxidizing the base with the formation of guanidin, thus demon- 

 strating positively the presence of this group in the arginin mole- 

 cule. Just as creatin is a methyl guanidin acetic acid so arginin 

 becomes guanidin-a-amido valerianic acid. On further examination 

 of the oxidation products Kutscher* obtained ;--guanidin butyric 

 acid and also succinic acid. The oxidation of arginin can be shown 

 as follows : 



I 



KH 



NH.CH,.CHj.CBL,.CH(NHj).COOH+0,=NH.CHj.CH,.CH,.COOH+NH,+CO,. 



ABQININ. y-UUAHIDIN-BDTYKIC ACID. 



' Berichie, 31, 3183 (1898) : Zeits. physiol. Chem., 29, 334. 



'JBerichte, 34, 454 (1901). 



^ Zeits. physiol. Chem., 32, 278. 



* Zeits. physiol. Ohem., 32, 413. 



