STUDIES IN THE PHYSIOLOGY OF THE FUNGI 
XIII. Tue Errkcr or HxpRoGEN-IoN CONCENTRATION UPON 
THE ACCUMULATION AND ACTIVATION OF AMYLASE 
PRODUCED BY CERTAIN FUNGI 
JOANNE L. KARRER 
Research Assistant to the Missouri Botanical Garden 
INTRODUCTION 
The effect of the hydrogen- and hydroxyl-ion concentration 
upon the growth of organisms, in general, has received consider- 
able attention in late years, but the effect of these ions upon 
the individual processes produced by an organism has not been 
so thoroughly studied. It has been repeatedly shown that cer- 
tain fungi require an acid medium to produce maximum growth, 
while others require alkaline conditions. These diverse rela- 
tions would seem to indicate a difference in the production, 
accumulation, and activation of the various enzymes concerned 
in the growth of these organisms. Recent work has indicated 
a difference in animal and plant proteolytic enzymes, and it has 
been shown that plant amylases require a range in conditions 
different from pancreatic amylase, with regard to activity. In 
plants, secretion amylase has been found to have properties 
quite different from those of translocation amylase. 
It has been the purpose of this investigation to study and com- 
pare the amylases produced by fungi requiring different ranges 
of H-ion concentration for growth. An attempt has been made 
to determine the effect of acidity and alkalinity upon the secre- 
tion and accumulation of the enzyme. Further, an endeavor 
has been made to determine whether the enzymes produced 
under these conditions have similar activities in buffered solu- 
tions covering a range of H-ion concentrations, and whether there 
is any correlation between the optimum for activity and the op- 
timum for secretion and accumulation. It was considered 
unnecessary to determine the effect of the H ions apart from 
the other ions in the buffered solution, since the purpose was 
not to determine the absolute optimum H-ion concentration for 
the activity of the enzymes but merely to produce a set of similar 
ANN. Mo. Bor. Garb., Vor. 8, 1921 (63) 
