118 CHEMISTRY OF BACTERIA AND THEIR PRODUCTS 



proteids, are but very slightly toxic, and of little pathological 

 importance. 



When we examine the structural formulae of some of the 

 larger ptotnam molecules and compare them with the formulae 

 of the amino-acids that form the proteid molecule, the relation 

 is apparent, e. g., compare iso-amylamin with leucin. 



- CH 2 CH 2 - NH 3 >CH - CH 2 CH - NH 2 



CH / \nnnw 



(iso-amylamin) (leucinj *-/<JUii. 



Putresdn, C 4 H 12 N 2 , structural formula, 



NH 2 CH 2 CH 2 CH 2 CH 2 NH 2 , 

 and cadaverin, C 5 H 14 N 2 , structural formula, 



NH 2 CH 2 CH 2 CH 2 CH 2 CH 2 - NH 2 , 



are of interest because they have been found in the intestinal 

 contents, arising from putrefaction of proteids, and also are 

 sometimes present in the urine in cystinuria. 1 They are closely 

 related to the diamino-acids, lysin and ornithin. They are but 

 slightly toxic, although capable of causing local necrosis when 

 injected subcutaneously. (See further discussion in Chapter xix.) 

 The Cholin Group. Another group of ptornams, includ- 

 ing cholin and closely related substances, is also of interest. 

 These ptomams are : 



Cholin, CH 2 OH CH 2 N(CH,) 8 OH 



Neurin, CH 2 = CH N(CH 3 ) 3 OH 



Muscarin, 8 CH (OH) 2 CH 2 N(CH 3 ) 3 OH 

 Betain COOH CH 2 N(CH 3 ) 3 OH 



The first point of importance is that cholin is present in every 

 cell normally, forming the nitrogenous portion of the lecithin 

 molecule. Its source in putrefaction of tissues is, therefore, 

 plain. Furthermore, it seems to be liberated during life when- 

 ever nervous tissue, which is rich in lecithin, is broken down in 

 any considerable amount. Mott and Halliburton 3 claim that 

 it can be found in both the blood and the cerebrospinal fluid 

 of man and animals suffering with severe nervous lesions. 4 



1 UdranszkyandBaumann, Zeit physiol. Chem.,1889(13),562; 1889(15), 77. 



2 Other structural formulae have been given for muscarin, e.g., 



CH 2 (OH) CHOH N(CH 3 ) 3 OH. 



3 See Halliburton, " Chemistry of Muscle and Nerve," Philadelphia, 1904. 

 * Coriat (Amer. Jour, of Physiol., 1904 (12), 353) has studied the conditions 



under which cholin may be produced from lecithin. Putrefaction of lecithin 

 or lecithin- rich tissues liberates cholin, as also does autolysis of brain tissue ; 

 neither pepsin nor trypsin, however, splits it from the lecithin. In brain tissue, 

 therefore, there seems to be an enzyme different from trypsin, which splits 

 cholin out of the lecithin molecule. 



