1921] 
KARRER—H-ION CONCENTRATION AND AMYLASE ACTION 87 
cells to nutrient solutions. If it had beer: possible to grow the 
various organisms used in this investigation for several gener- 
ations upon media having extreme H-ion concentrations with 
relation to growth more striking results might have been ob- 
tained. 
Differences with respect 
to activity range in the k 
buffer solution will be 
noted in a comparison of 
the curves of the various 
organisms. Fusarium 
and Colletotrichum resem- 
bled each other, while E V E: 
Penicillium possessed p 
characteristics somewhat 
+ /o 
unlike either of these. E: 
In the former, maximum = 
activity occurred at Py 95$ 
6.0, a gradual decrease V 
followed as the solutions 8 
became morealkaline,and 6 
complete inhibition oc- 
curred at P 49.00r11.0,de- i 
pending upon the amount 
of amylase present in the 
original enzyme disper- 2 
sion. In the latter, on 
the other hand, a zone of 
maximum action oc- P. = 
^H 
curred between P 3.0, or 
lower, to P, 6.0, and ac- Fig. 8. Action of extracellular (——) and 
tivity definitel d at intracellular (---) amylase produced by Colle- 
vay HUS ceased B». RM Gossypii grown in Czapek's solution 
P, 8.0. Eventhoughthe of p, 8.2. 
enzymesw tpurified, 
the results would seem to indicate that in Penicillium an amylase 
was formed which had properties somewhat different, at least 
in regard to activation by the H,PO,-NaOH-starch buffer solution 
employed for measuring amylase activity. 
It was not the purpose of this investigation to establish defi- 
nite maxima for the amylases produced by these organisms, 
7 7 it 
