[Vor. 8 
68 ANNALS OF THE MISSOURI BOTANICAL GARDEN 
saccharogenic action as determined by the reduction of Fehl- 
ing's solution. 
In a later paper by Sherman and Walter (17), the action of a 
very concentrated preparation of malt amylase on purified 
soluble starch was investigated by observing the rate of forma- 
tion of maltose in neutral solutions without electrolytes and in 
solutions containing regulated amounts of HCl, H,PO, and 
KH,PO,. When the optimum H-ion concentration, Cy = 
1 x 10™*‘, was reached, the action of the enzyme was increased 
at all stages. This optimum was the same for all of the above 
electrolytes. The greater the concentration of the enzyme, the 
less the effect of the electrolyte. 
Sherman, Thomas, and Baldwin (’19) recently studied puri- 
fied amylases obtained from three different sources,in order to 
determine the optimum H-ion concentration and to establish 
the “limits of H-ion concentration within which any enzymic 
activity is shown and the form of the curve representing the 
activities at all concentrations of H-ions between these limits.” 
Pancreatic and malt amylase and the amylase of Aspergillus 
Oryzae were chosen as representative of the enzyme as it occurs 
in higher animals, higher plants, and fungi, respectively. The 
activity of the enzymes was studied in solutions having a range 
of approximately Py 2-10. These solutions contained H,PO, 
and NaH,PO, Na,HPO, and Na,CO, and, in some cases, 
NaH,PO, or Na,HPO, The action of the enzyme upon the 
substrate took place at 40? C. and the analyses were made with 
Fehling's solution. The results showed that pancreatic amy- 
lase was active within a range of Pa 4-10, the optimum being at 
about Py 7. Malt amylase was active between Py 2.5-9, with 
an optimum at Py 4.44.5, and the amylase of Aspergillus Oryzae 
showed activity between P, 2.6-8, with an optimum at about 
Pu 4.8. It was thus shown that the amylase of malt and Asper- 
gillus Oryzae possessed similar saccharogenic powers in the 
solutions used in the experiment, while pancreatic amylase not 
only had a different range in activity but also possessed a higher 
optimum. The influence of the electrolyte, as distinguished 
from the H-ion concentration alone, seemed greatest in the case 
of pancreatic amylase and least in the case of the amylase of 
Aspergillus Oryzae. 
