SOLUBLE, NITROGENOUS CONSTITUENTS OF PLANTS 33 
SOLUBLE NITROGEN 
Ne Saraca indica L. 

—BUTANOL—ACETIC-WATER —————> 
<—__ PFENOL - WATER 
Fig. 8. The ninhydrin-reactive, alcohol-soluble compounds of the seeds of Savaca indica L. Spots 
numbered 2—23 follow the convention of Fig. 1; No. 26 represents pipecolic acid; No. 29 (brown) 
represents y-methyleneglutamine; No. 30 (brown) represents y-methy leneglutamic acid. Spots 
designated Leg. Nos. 173-175 represent unidentified substances encountered in this and other 
legumes (cf. Fig. 2). 
of pipecolic acid and, in addition, two compounds that can be recognized from work 
which is now to be summarized, as y-methyleneglutamine (No. 29 on the figure) and 
y-methyleneglutamic acid (No. 30). 
y-Substituted glutamyl compounds 
Discovered first in legumes and in tulip, y-methyleneglutamic acid and its amide 
seemed as though they could be derived theoretically from the aldol condensation of 
two molecules of pyruvic acid. However, another compound now proves to be of 
more general significance. Although prepared from the keto acid (pyruvic aldol) 
before it was known to occur in nature, this amino acid was discovered first in 
Adiantum (Fig. 9, STEWARD, WETMORE AND POLLARD*®). This compound, as syn- 
thesized from pyruvic aldol, is y-hydroxy-y-methylglutamic acid (GROBBELAAR, 
POLLARD AND STEWARD!*). As in the case of the hydroxypipecolic acids, here also 
there are 4 diastereoisomeric possibilities, and it is not yet known which, or how many, 
of these are naturally occurring. 
From the y-hydroxy-y-methylglutamic acid, however, many possible metabolic 
pathways may stem, leading to a wide variety of metabolites (STEWARD AND Por- 
LARD®8), On careful examination it transpires that this compound occurs in small 
amount on chromatograms of extracts of tulip (Fig. 10), although to show this the 
chromatograms needed to be somewhat overloaded with respect to the other con- 
References p. 42 
