30 E.G. STEWARD AND Ji. Ko POLLARD 
tai 
4 
4 
Butanol - Acetic Acids 

AZETIDINE-2— 
CARBOXYLIC ACID 
Fig. 4. The ninhydrin-reactive, alcohol-soluble compounds of the lily of the valley (Gone 
majelis). Note: azetidine-2-carboxylic acid (brown). 
Pripecolic acid ; the substituted prperidines ; cyclization from diamino acids 
Piperidine-2-carboxylic acid was seen by ZACHARIUS (STEWARD AND THOMPSON*?; 
ZACHARIUS*®) in this laboratory in extracts of the ovary wall and seed of the green 
bean and later identified (ZACHARIUS, THOMPSON AND STEWARD?®’) ; it arises by elimi- 
nation of ammonia and by ring formation from lysine (GROBBELAAR AND STEWARD!"). 
From this point this acid has been reported from many angiosperms. Apparently 
lysine which is diverted to pipecolic acid is lost to protein synthesis, for any sub- 
sequent metabolism seems to proceed via a-aminoadipic acid (seen by GROBBELAAR!, 
1955, In the pedicels of Phaseolus, as shown in Fig. 3) and thence to glutaric acid 
TABLE I 
DISTRIBUTION OF SOME RECENTLY IDENTIFIED AMINO ACIDS 
THROUGHOUT THE LILIACEAE!® 

Found in 
Species Genera 

Amino acid 

y-Methyleneglutamice acid 23 7 
y-Methyleneglutamine 17 2 
y-Methylglutamic acid 19 6 
y-Hydroxy-y-methylglutamic acid 16 6 
y-Hydroxyglutamic acid 3 2 
Azetidine-2-carboxylic acid 23 17 
Pipecolic acid 9 9 

References p. 42 
