E52 J. R. SIMMONS AND H. K. MITCHELL 
concentration was about 3 times that of either of the other amino acids. The overall 
increase in ninhydrin reactivity following hydrolysis was about 2-fold. Component B 
separated cleanly from glutamic acid on chromatography in the propanol—water 
solvent. Hydrolysis followed by two-dimensional chromatography revealed 4 nin- 
hydrin-positive spots, probably lysine, glycine and aspartic acid in addition to glutamic 
acid. The intensity of the ninhydrin color of the glutamic acid spot was about 4 times 
that of lysine and aspartic acid and about twice that of the glycine. The overall in- 
crease on hydrolysis was again about 2-fold. 
The results obtained by injecting A and B and then determining protein-specific 











m10 
1 
i) Leucine + 
x Amino acids 
S 
£8 
~ 
2 
=a Leucine 
iS 
iS 
ic 
a4 
$B} 
jc 
a Glutamic Acid + 
O Amino acids 



ine) 
Glutamic acid 
20 
Time (min) 
Fig. 5. 84-h larvae were injected with a solution (3 wC/10 yl) of the radioactive amino acid, with 
and without added essential amino acids. Ten larvae were injected for each time interval and the 
specific activity of an extracted protein preparation was determined. 
activity are given in Fig. 4, and are compared with the result of a control experiment. 
The results leave little doubt that both A and B are different from free glutamic acid 
with respect to incorporation into larval protein. Whether the incorporation proceeds 
directly from the injected component A and B or first is hydrolyzed to the level of free 
glutamic acid is not determinable with the limited information now available. 
Incorporation of amino acid into protein. The limited amount of information obtainable 
from paper chromatograms of squashed larvae indicated that most of the radio- 
active material found at the chromatographic origin is protein though there is also 
some large peptidic material present. To obtain a more direct measure of incorporation 
of amino acids into larvae, extracts were made and the specific radioactivity of pro- 
teins was determined. The results of such experiments using two [!4C] amino acids 
are shown in Fig. 5. The findings are in good agreement with those of the direct squash 
experiment. The slow incorporation of glutamic acid into protein is typical of the 
non-essential amino acids (glutamic acid, aspartic acid, glycine and alanine) which 
were tested while the essential amino acids, leucine and valine both show more rapid 
incorporation into protein. The addition of an amino acid mixture (acid hydrolyzate 
of Drosophila protein) to the injection mixture enhanced the incorporation of both 
glutamic acid and leucine into protein. 
References p. 155 
