570 J. T. HOLDEN 
The values presented in Table II are cited only to show the general magnitude of 
pool sizes. Considerable variability originating from as yet undescribed causes has 
been encountered, for example, by separate groups working with FE. coli. The culture 
of L. arabinosus used in this laboratory recently suffered an abrupt 35°% loss in 
glutamate accumulation capacity which is as yet unexplained. GALE observed that 
over a period of a few years S. aureus increased its ability to accumulate glutamic 
acid. Such observations are experimental curiosities at present. 
The possibility that pools are not homogeneous has been suggested by the studies 
of CowlE AND McCLurRE* who found that Candida utilis accumulates amino acids in 
TABEEAL 
AMINO ACID ACCUMULATION CAPACITIES OF VARIOUS MICROORGANISMS 


Maximum Maximum 
Organism Amino acid capacity* concentration Ref. Numbers 
pemoles|/Too mg ratio** 
L. avabinosus Glutamic acid 68 390 54 
Alanine 30 250 52 
Threonine 18 52 
Glycine 14 52 
Proline 14 58 52 
Valine 9 45 52 
S. faecalis R Glutamic acid 43 200 52 
Alanine 22 150 52 
Threonine 30 2 
Glycine 23 52 
Lysine 2 180 52 
Arginine 16 52 
S. faecalis Glutamic acid 22 300 31 
S. aureus Glutamic acid 47 600 31 
E. coli Proline DAE 1000 12 
Valine 6.0 2200§ 12 
E. coli Valine Te 460 21 
E. coli Proline 3.4 50 58A 
E. colt Tryptophane 2..5 W 
Dutch Top Yeast Glutamic acid 61 III 
S. ceveviseae Glutamic acid 45 210 41 
Arginine 2 985 41 
Lysine 22 815 41 
C. utilis Threonine 44 22 
N. crassa Proline Bit 2 118 

* Values are for 100 mg dry weight of cells. A majority of the values are taken from exper- 
iments in which the effect on pool size of varying the extracellular concentration was determined. 
Reasonable estimates are given for cases in which pool sizes increase slowly as external concen- 
tration is raised over a wide range. Where the effect of external concentration was not studied, 
the largest pool size reported is cited. 
** In most cases, the values shown were cited in the original publication and refer to the 
ratio: internal concentration/external concentration, assuming the internal amino acid to be 
distributed throughout all the intracellular water. Generally maximal ratios are observed at 
relatively low extracellular concentrations, far below those which are required to saturate the 
pool. 
*** Proline or a mix of amino acids can be accumulated to levels as high as 100 yxmoles/100 mg 
by adding high concentrations of sucrose to the medium. 
§ An extracellular proline concentration of 0.0029 wmoles/ml was used. A ratio of 18 000 was 
reported using an extracellular concentration of 0.016 mumoles/ml. 
References p. 592/594 
