1921] 
KARRER—H-ION CONCENTRATION AND AMYLASE ACTION 85 
From the two series of cultures of Pericillium (figs. 10-11 
and table v), it is evident that the effect of the buffer solution 
upon amyloclastic activity of the intraand extracellular enzyme 
in general produced the same 
results. The range of activity 
extended from below P 4 3.0 to 
Pa 8.0 where complete inhibi- 
tion occurred. The amylase 
as produced by this organism 
did not have a sharply defined 
optimum acidity. Any H-ion 
concentration between P, 3.0 
and 6.0 seemed to be equally 
favorable for both the extra- 
cellular and intracellular en- 
zyme action. 
m aN 
$ LA 3 
E! À 
b E. 
$ = 
Pu 3 S 
Fig. 5. Action of extracellular (——) 
and intracellular (- - -) amylase produced 
by Fusarium sp. grown in Czapek's solu- 
tion of Pg 9.2. 
It is worthy of note that when the activity of amylase in all 
of the series studied was measured in distilled water instead of 
10 
the suffer solution (tables 
11-17) theresults obtained 
agreed closely with those 
of tk.ecorrespondingH-ion 
concentrations of the 
buffer solution, thus in- 
dicating that at these re- 
actions the ions other 
than the H ions in the 
buffer solution had little 
effect. The distilled 
water used had an H-ion 
concentration of P, 5.4— 
5.8, but uponthe addition 
of tae enzyme dispersion 
Py. 5 
Fig. 6. Action of extracellular ( 
intracellular (- --) amylase produced by Colle- 
totrichum Gossypit grown in Czapek's solution 
of Pa4.5. 
g 7 
this was shifted toward 
alke linity. 
When the influences 
of the H-ion concen- 
tration upon the enzyme 
yind 
secreted by the same fungus grown ir. nutrient solutions 
containing varying amounts of acidity ancl alkalinity are com- 
