307 



Amino Acids and Related Compounds 



views are available*"' ^^' ■*- and references to some of the vast 

 literature on this subject can be found there. 



The occurrence studies cited demonstrate the importance of 

 glutamic acid. It is a constituent of folic acid and related sub- 

 stances, and of glutathione, and various antibiotics. It occurs 

 in the cell wall of bacteria and, as a polypeptide, is the sole 

 capsular substance of certain bacilli. Its wide distribution re- 

 flects its cross-roads position in nitrogen metabolism. 



Synthesis of glutamic acid by most aerobic microorganisms 

 involves ainination of a-ketoglutaric acid (a reversible reac- 

 tion), thus tying it in with the citric acid cycle. It is a pre- 

 cursor of ornithine, proline and in some cases lysine. 



O 



I amination 

 HOOC— CHo— CH,— C— COOH ;:^ ^ HOOC— CHo— CH2— CH— COOH 



a-Ketoglutaric Acid I 



NH2 



Glutamic Acid 



In E. coli, at least, the route to ornithine involves N-acetylated 

 intermediates. The intermediates shown accumulate in appro- 

 HOOC— CHo— CH2— CH— COOH 



Proline 



30 Bernard D. Davis, Advances in Enzymol. 16 247-312 (1955). 



^'^ Alton Melster, "Biochemistry of the Amino Acids," Academic 

 Press, New York, 1957, pp. 256-394. 



■^-Joseph S. Fruton and Sofia Simmonds, "General Biochemistry," 

 John Wiley and Sons, Inc., New York, 1958, pp. 771-896. 



