56 J. F. THOMPSON et al. 
y-L-Glutamyl-hypoglycin (hypoglycin B). Two crystalline substances were isolated! 
from the fruit of the ackee (lighta sapida) which causes Jamaican vomiting sickness 
and a reduction in blood-sugar level. The crystalline materials cause hypoglycemia. 
One of these (hypoglycin A) has been shown to be an a-amino acid with a cyclopropane 
ring (L-a-amino-/-(2-methylenecyclopropyl)propionic acid)!®. The second substance 
(hypoglycin B) has less physiological action on a weight basis. It was found to be 
the y-glutamyl peptide of hypoglycin A by degradation to glutamic acid and hypo- 
glycin A (ref. 6). The y-glutamyl linkage was demonstrated by reaction of fluoro- 
dinitrobenzene with the glutamic acid portion and formation of 2 moles of nitrogen per 
mole of peptide in the nitrous acid reaction. Final proof was obtained by synthesis of 
a y-glutamyl peptide from isolated hypoglycin A which was the same as the isolated 
peptide. 
y-Glutamylvaline. This dipeptide was obtained from the non-protein fraction of the 
onion bulbs in crystalline form®. Hydrolytic degradation gave L-glutamic acid and 
valine. 
y-Glutamylisoleucine. Another dipeptide was isolated from onion bulbs by chromato- 
graphy on Dowex-1 (ref. 5) with acetic acid. Acid hydrolysis gave two compounds 
which cochromatographed with isoleucine and glutamic acid. 
y-Glutamylalanine. VIRTANEN AND BERG? isolated material from a spot on paper 
chromatograms of 70° ethanol extracts of pea seedlings (Pisum sativum). This 
material hydrolyzed to two compounds which cochromatographed with glutamic acid 
and alanine. 
y-Glutamylmethionine. An acid-labile substance has been purified from an alcohol 
extract of kidney bean seed by paper chromatography. The unhydrolyzed material 
gave a positive test for a sulfur amino acid with the iodoplatinate reagent!® and a 
positive test for an alpha amino acid with pyridoxal!’. The hydrolytic products cochro- 
matographed with glutamic acid and methionine. 
y-Glutamylethylamine (Theanine). This ethyl amide was isolated from the non- 
protein fraction of tea leaves (Camellia sinensis) and mushrooms (Xerocomus ba- 
dius )'*, 13. The hydrolytic products were found to be t-glutamic acid and ethylamine 
and this was consistent with the elemental analysis. The structure was confirmed by 
synthesis!*. This compound could be a decarboxylation product of either y-glutamyl- 
f-alanine or y-glutamylalanine. 
y-Glutamyl-b-aminopropionitrile (Lathyrus factor). A substance which is capable of 
producing skeletal abnormalities in rats has been isolated in pure form from Sweet 
pea seeds (Lathyrus odoratus)’. The compound was hydrolyzed to L-glutamic acid, 
ammonia and /-alanine. Elemental analysis indicated that the original compound was 
a nitrile. The y-glutamyl-$-propionitrile was synthesized and found to be identical 
with the isolated substance by infrared and melting point!!. This compound has an 
obvious chemical similarity to y-glutamyl-f-alanine and it remains to be seen whether 
there is a biochemical relationship. 
References p. 64 
