Feb. 1, 1925 
Decomposition of Proteins and Amino Acids 
267 
the fact that the initial reaction of the 
medium was about pH 7.0 to 7.3 and 
the medium is not very highly buffered, 
the reaction changed rapidly to pH 8.0 
and even 8.6, which seems to be about 
the limiting reaction for the growth of 
at least the two fungi studied. In one 
case (with 1 per cent glutamic acid) 
the reaction was left by mistake unad¬ 
justed at a pH of 3.0. The bacteria 
and Actinomyces made no growth, since 
the reaction was too acid for their de¬ 
velopment, but the two fungi made a 
very excellent growth. This shows 
that there are various factors to be con¬ 
sidered in the study of utilization of 
organic substances under artificial con¬ 
ditions, especially by pure cultures of 
microorganisms. Notwithstanding the 
statements made that fungi are not af¬ 
fected by wide ranges in reaction, there 
is no doubt that, starting with a reac¬ 
tion of about pH 6.0 to 7.0, they will 
be more favored by the presence of 
substances which result in products 
tending to make the reaction acid rather 
than alkaline; and in the presence of 
alkaline-forming substances they will 
be more favored by an acid than by an 
alkaline or even a neutral reaction. 
In connection with the utilization of 
racemic compounds by microorgan¬ 
isms, attention should be called to the 
extensive literature on this subject 
since the work of Pasteur. According 
to Ehrlich ( 6 ), cZZ-proline, cZZ-aspartic 
acid and dZ-tyrosine are acted upon by 
yeasts symmetrically, whereas dZ-al- 
anine, dZ-glutamic acid and others are 
acted upon asymmetrically. Prings- 
heim {20) as well as Neuberg {19) 
found that dZ-glutamic acid and dZ- 
aspartic acid are acted upon by fungi 
and bacteria symmetrically. Various 
other investigators have shown that, 
while some organisms attack some 
amino acids symmetrically, other or¬ 
ganisms attack the same acids asym¬ 
metrically, depending on the nature of 
the compound and the organism. 
DECOMPOSITION OF GLYCOCOLL 
(GLYCINE) 
The chemical formula for glycocoll is 
CH 2 . (NH 2 ). COOH; in other words, it 
contains theoretically 18.67 per cent 
nitrogen and 32.0 per cent of carbon, 
the ratio between the carbon and nitro¬ 
gen being 1.7. According to Levene 
and Van Slyke {16), the amount of 
amino acid obtained for gly cocoll, by 
the Van Slyke method, is somewhat 
higher than its actual nitrogen content; 
the figures obtained for amino nitrogen 
in the case of glycocoll should, there¬ 
fore, be multiplied by 0.93 to obtain 
correct values. Somewhat higher re¬ 
sults for the NH 2 — N in the case of 
this amino acid were actually obtained 
in our studies and the results were 
adjusted by multiplying the figures by 
0.93. The growth of only two organ¬ 
isms on glycocoll, in the absence of 
dextrose, is reported:Trichoderma and 
Actinomyces (Table I). These two 
organisms used up, in 12 and 15 days 
respectively, 29.8 and 41.1 mg. of 
the amino acid nitrogen and synthe¬ 
sized 50 and 59 mg. of dry mycelium. 
The Trichoderma produced ammonia 
equivalent to 24.28 mg. of nitrogen, or 
nearly 82 per cent of the amino acid 
decomposed; the Actinomyces pro¬ 
duced 30.46 mg. ammonia nitrogen, or 
74 per cent of the amino acid decom¬ 
posed. (The figures for NH 3 —N in¬ 
clude also the NH3 — N found in the 
control.) The Trichoderma assimi¬ 
lated over 44 per cent of the carbon 
decomposed (assuming that the myce¬ 
lium contains 45 per cent carbon), and 
the Actinomyces about 38 per cent. 
Where dextrose is present the ques¬ 
tion of carbon and nitrogen utilization 
by the organisms is somewhat more 
complicated. The Zygorhynchus de¬ 
composed, in 6 days, 22.7 mg. of the 
glycocoll nitrogen; and, in 10 days, 
42.1 mg. In view of the excess of dex¬ 
trose, most of the nitrogen has been 
reassimilated by the organism (17.63 mg. 
out of the 22.7 mg. decomposed) and a 
small amount is left as ammonia; in 
10 days all the dextrose has been used 
up, and the organism is forced to at¬ 
tack the amino acid molecule for its 
carbon, which is the reason for the 
more rapid decomposition and greater 
accumulation of ammonia. The same 
is true even to a more striking extent in 
the case of the Trichoderma. This 
organism has decomposed, in 5 days, 
glycocoll equivalent to only 48.6 mg. 
of nitrogen, 45.66 mg. of which has 
been reassimilated and resynthesized 
into fungous mycelium; only a trace of 
ammonia is found. However, after 10 
days, glycocoll equivalent to 108.2 mg. 
of nitrogen is decomposed, 49.03 mg. 
is found in the mycelium and 42.80 
mg. as ammonia. This is due to the 
fact that, after the organism has used 
up all the dextrose, it has to decom¬ 
pose the glycocoll as a source of carbon; 
so much so that the mycelium actu¬ 
ally began to undergo autolysis, as indi¬ 
cated by the diminishing weight. The 
fact that the nitrogen content of the 
mycelium did not decrease, while the 
total weight did, indicates that, after 
all the dextrose in the medium has been 
used up the organism will utilize as a 
source of energy certain carbohydrates 
