[Vor. 8 
84 ANNALS OF THE MISSOURI BOTANICAL GARDEN 
It will be seen from the curves (figs. 1-5) and tables m and 
III, representing the enzyme activity of Fusarium, that the effect 
of the buffer solution of various H-ion concentrations upon the 
extra-and intracellular amy- 
lase, produced in culture 
solutions of the same and 
/ N of different H-ion concen- 
\ trations, was similar. The 
/ \ ranges for activity did not 
e| | \ correspond in all cases, but 
, V this might have been due 
| E to the small amount of 
P, Pae Me enzyme material present 
which at even the optimum 
, Fig. 3. Action of extracellular PER = H-ion concentration hydro- 
geras (7) mile produced by lyzed only a small quantity 
of starch. It is also likely 
that under suchlow enzymic 
activity the differences in the original enzyme dispersion, which 
was the culture solution in one case and an extract of the 
mycelium in the other, might have been a factor. The amount 
of starch hydrolyzed at Py 3.0 varied, but a maximum was reached 
at P4 6.0 in all of the series. 
Asthe buffer solution approached 
6 
co “50 KMnO, 
alkalinity, enzyme activity de- 4 
creased until finally at Pa 11.0 ¢ 2 
there was complete inhibition. $ ÁO 
A rather uniform fall in the 2| _/ \ 
activity occurred from P 6.0 to x uc \ 
P, 11.0. 3 \ 
A similarity will also be noticed Py 3 5 7 9 
for the activity of extra- and Fi 
: ig. 4. Action of extracellular 
intracellular amylase produced (-—) and intracellular (- - -) amylase 
by Colletotrichum (figs. 6-9 and produced by Fusarium sp. grown in 
table 1v) at various H-ion con- Czapek’s solution of Px 8.2. 
centrations. Inhibition by acid 
occurred below P, 3.0 and maximum activity was reached at 
Py 6.0, beyond which there was a decrease, and at Pj 11.0 the 
enzyme was completely inhibited. 
