284 OCCURRENCE OF FREE AMINO ACIDS — VERTEBRATES 
FREE AMINO ACIDS IN ANIMALES iSSUrE 
EUGENE ROBERTS anp DAISY G. SIMONSEN 
Department of Biochemistry, Medical Research Institute, City of Hope Medical Center, 
Duarie, Calif. (U.S.A.) 
Early in our studies of the nitrogen metabolism of normal and neoplastic tissues! 
it appeared desirable to study the pools of non-protein amino acids and related 
substances. However, as in almost every biochemical field, progress was slow and 
curlosity limited until methods became available which enabled a large number of 
determinations to be made in a reasonably short period of time. The development 
of two-dimensional paper-chromatographic procedures, by which it was possible to 
detect microgram quantities of substances for which other adequate microanalytical 
procedures were not available?~*, made it feasible to survey rapidly the distribution 
of free or loosely bound amino acids and other ninhydrin-reactive substances in a 
variety of animal tissues. The paper-chromatographic procedures furnished tools 
which were ideally suited for giving simultaneous information rapidly about the 
maximal number of ninhydrin-reactive constituents, and although often employed 
in a semi-quantitative fashion, could give valuable hints about the presence of new 
materials and could indicate which substances should be studied further in particular 
biological situations. Column-chromatographic methods have also been applied 
extensively, but the procedures, although quantitative, are more time consuming 
and allow fewer samples to be examined (see ref. 6 and paper by WINItTz in this 
Symposium for review of analytical methods). 
As the work developed it became apparent that the perceptions of the patterns 
of the spots of the different constituents on the chromatograms were more meaning- 
ful to most workers than the same data given in lists of names of the constituents 
followed by numbers designating the amounts, or in bar graphs, etc. Most human 
computers seem to be able to store and retrieve the patterned, pictorial information 
more effectively and to relate it to metabolic events more rapidly than they can the 
numerical representation of the same information. One might wonder whether the 
transmittal of some types of numerical information about multivariant situations, 
in general, from non-human computers to human recipients could be made more 
effective if the information were transformed into quantitative, pictorial patterns 
resembling those seen on paper chromatograms! 
SOME GENERAL REMARKS ABOUT DATA FROM EXTENSIVE SURVEYS 
OF FREE AMINO ACIDS OF TISSUES 
The first application of the two-dimensional paper-chromatographic technique to 
protein-free extracts prepared from mammalian tissues immediately after removal 
References p. 348/349 
