LTSm. 445 



Since lysin is a homologue of omithin it is possible that like the latter 

 it exists in the proteid molecule in combination with an urea residue. 

 In other words it may have a parent substance which bears to it the 

 same relation that arginin does to ornithin. This theoretical body 

 would possess the formula C^HjgNp^ • On hydration it would yield 

 urea and lysin in the same way that arginin yields urea and omithin. 

 In this way perhaps may be explained the origin of the ammonia 

 which is formed during the hydrolysis of proteids (see table, p. 426). 

 The existence of the ptomam hexamethylene diamin may be taken to 

 indicate a still higher homologue. The relation of these bodies may 

 be indicated thus : 



Arginin, CjHmNiO, = Omithin, C5H„N,0j = Putresoin, C^HuN,. 



= Lysin, CjHuNjOj = Cadaverin, GjHHNr 



= Hexa^met. -diamin, CsHmN,. 



Lysin is easily soluble in water and, like arginin and histidin, it is 

 not precipitated on saturation with ammonium sulphate but is pre- 

 cipitated by alcohol and by phosphotungstic acid. Hence the pres- 

 ence of these bases in antipepton (Kutscher). Unlike the other two 

 bases lysin is not precipitated by silver nitrate and fixed alkali, and 

 this fact Kossel makes use of to effect their separation (p. 428). 

 The free base can be obtained best from the sulphate. On heating 

 it gives off alkaline vapors (Drechsel, Kruger). On fusion with 

 alkali it jaelds acetic and propionic acids (Henderson). 



In the tryptic digestion of sturin Kossel and Mathews obtained 

 a compound, CjjHjjNyOj , which crystallized in needles and was evi- 

 dently a combination of two molecules of lysin with one of histidin. 

 The lysatinin (p. 425) of Drechsel is apparently a similar combina- 

 tion of one molecule each of lysin and of arginin. 



The dichlorid, C5Hj^N202.2HCl, can be prepared from the picrate 

 or from the platinum salt. It melts at 217° and at 261° it decom- 

 poses yielding hydrochloric acid, carbon monoxid, water and a 

 sublimate of ammonium chlorid. Drechsel' interpreted this reac- 

 tion as leading to amido valeric aldehyde which by loss of water should 

 yield tetrahydropyridin but this transformation, which would be 

 analogous to the change of cadaverin into piperidin, has not as yet 

 been realized. According to Henderson it melts at 192-193°; 

 while Lawrow^ states that it begins to melt at 194-195° and gives 

 off gas at 200-202°. It is not changed to the monochlorid by pro- 

 longed heating at 130°. The aqueous solution is strongly acid and 

 on evaporation with the alkali it forms bases possessing a slight 

 coniin-like odor (Drechsel). The colorless crystals are but slightly 

 soluble in alcohol ; readily soluble in methyl alcohol, and readily 

 form from aqueous solution on concentration. 



The salt as well as the free base are dextro-rotatory and the devia- 



•SmcAte, 25, 2455, 3504. 

 'ZeUs.physiol. Chem., 28, 395 ; 29, 321. 



