DECOMPOSITION OF ORGANIC COMPOUND 231 



thus developed are malodorous. A few are distinctly poison- 

 ous. For example, the histamin formed by the decarboxyla- 

 tion of the amino acid called histidin is extremely poisonous. 

 Among the ptomaines (amines) most commonly produced 

 by microorganisms is trimethylamin (CH3)3N. This gives 

 a characteristic odor to herring brine and decaying fish. It 

 is produced in pure cultures by certain bacteria. It is not 

 highly poisonous. Other ptomaines which have been iso- 

 lated are putrescin (tetramethylenediamin, NHjC^HgNHj) 

 and cadaverin (pentamethylenediamin, NHjCgHioNHj) and 

 neurin (CH3)3C2ll3NOH. The latter is very poisonous. It 

 should be noted that apparently food poisoning is but 

 rarely due to the presence of ptomaines. Most of the cases 

 of ptomaine poisoning which have been recorded in the 

 literature or which are popularly supposed to be of this 

 type are in reality either infections with specific bacteria 

 or are the result of eating foods containing true toxins or 

 endotoxins produced by the specific bacteria, and are not 

 primarily the result of a decomposed protein. 



Certain microorganisms, particularly yeasts, change 

 amino acids by hydrolysis to a primary alcohol, at the same 

 time bringing about decarboxylation and deaminization. 

 For example : 



CH3CHNH2COOH -f HjO = CH3CH2OH -I- NH2 -h CO2 

 Alanin Ethyl alcohol 



One of the common products in alcoholic fermentation is 

 amyl alcohol or so-called fusel oil. This is produced by 

 yeasts from isoleucin. The reaction may be illustrated as 

 follows : 



C.H^^NH^COOH + H,0 = C^H.^OH + NH3 + CO, 

 Isoleucin Amyl alcohol 



The amyl alcohol thus formed finds extensive use in the 

 industries, particularly in the form of amyl acetate. 



