15 



Amines 



Much remains to be learned concerning the earlier stages of 

 nitrogen metabolism in microorganisms. Practically, the abil- 

 ity of certain soil bacteria (in combination with legumes) to fix 

 gaseous nitrogen has been exploited for many years. Research 

 in this area has been reviewed.^ Ammonia, methane, hydrogen 

 and water probably were present in the atmosphere of the primi- 

 tive earth, and it has been shown- that amino acids can be 

 formed by electric discharges through such mixtures. 



While we are primarily concerned in this compilation with 

 metabolites isolated from microorganisms growing in the wild 

 state or cultivated on an essentially glucose medium, the more 

 complex amines are generally only remotely derived from sugar, 

 often by way of the amino acids. A large hterature exists on 

 the ability of bacteria to decarboxylate amino acids to amines, 

 these experiments generally involving addition of the amino 

 acid to the medium. It has been shown,^ however, that many 

 bacteria which produce amines on a casein hydrolysate medium 

 do not do so on a synthetic medium with ammonium salts the 

 only nitrogen source. Studies with Escherichia coli* indicate 

 that aspartic acid and alanine and perhaps glutamic acid serve 

 as important nitrogen entry vehicles. These acids can supply 

 the total nitrogen requirement if no ammonium ion is available, 



^ William D. McElroy and Bentley Glass, "Inorganic Nitrogen 

 Metabolism," Johns Hopkins Press, Baltimore, 1956. 



2 Stanley L. Miller, Science 117 528 (1953); idem., J. Am. Chem. 

 Soc. 77 2351 (1955). 



3 H. Proom and A. J. Woiwod, J. Gen. Microbiol. 5 930 (1951). 



* "Studies of Biosynthesis in E. coli," Carnegie Institute of Wash- 

 ington Publication 607, Washington, 1955. 



