METABOLISM OF PEPTIDES IN DROSOPHILA 149 
glutamic acid in the more rapid incorporation of radioactivity into compounds re- 
maining at the origin of the chromatogram. Hydrolysis of substances from various 
areas of the chromatograms resulted in the recovery of material which corresponded 
chromatographically to leucine, plus other ninhydrin-positive material. However, at 
30 min, only about half as much of the non-origin radioactive material hydrolyzed 
to the amino acid as was the case when glutamic acid was used. On the basis of the 
300 
pe) 
e) 
e) 
Counts/min 
fo) 
fo) 
O Sp eee 
7 SS (43) 7 (2 
Fig. 2. Distribution of radioactivity resulting from the paper chromatography of squashed whole 
animals injected with [14C] leucine (to wC/20 yl). Numbers indicate areas measured by planimeter 
with 1 being the chromatographic origin and 6 most closely matching the position of known leucine. 
direct squash chromatograms of animals which have been injected with leucine it is 
difficult to draw any conclusions regarding the homogeneity of a given radioactive 
area. At some stages of the time series recorded in Table II there were well-defined peaks 
at the chromatographic positions indicated. At both earlier and later times these 
same areas could not be distinguished from adjacent areas on the basis of radioactivity. 
It seems probable that different compounds were being measured at different points 
in the time series. This supposition is supported by the tendency for the point of 
greatest radioactivity to shift with time, even though it occurs in the same general area. 
The leucine pattern is marked by the rapid formation of radioactive material which, 
with the exception of the substances at the origin, shows little quantitative change 
TABLE II 
LEUCINE INCORPORATION 
84-h larvae were injected with a solution of 10 wC/20 wl of L-leucine and three larvae were squashed 
on Whatman No. 1 paper at the time from injection indicated. After chromatography in the pro- 
panol-NH, solvent the chromatograms were scanned with the strip counter and the areas deter- 
mined by planimetry. Radioactivity is reported as the per cent of total radioactivity present. 
Areas refer to those designated in Fig. 2. 



Rime Total % of total radioactivity at area 
(min) area . 3 2 y j - 5 6 x 
1.5 5.184 0.8 0.7 1.6 1.331 2.3 92.8 0.9 
3 5-349 Del 2.0 NeF 3.9 Fst 79.3 1.1 
5 3.886 4.3 1.8 1.4 1.5 6.3 83.1 1.6 
10 3.86 11.7 itay2 3.1 3.0 6.4 Fag? 3-4 
30 4.01 19.4 10.7 4.2 5-7 4.6 53-0 1.8 
60 5.985 23.9 3.3 4.6 3.0 6.4 57-7 1.2 
140 3.909 54.8 8.3 10.5 3.4 352 18.2 1.6 

References p. 155 
