1952 Volume 47 Issue 12 Pages 523-512
A great number of researches and experiments have been reported regarding the influence of various kinds of salts on the action of diastase. However, they contain some conflictions and disagreements in the results chiefly owing to the lack of knowledge in the structure of diastase and to the difficulties of experiments. It is necessary, therefore, to recognize that the results of such studies are limitted more or less strictly to the conditions and the methods of experiments.
We compared the influences of salts on the action of diastase by the following method: The solution of diastase prepared by the alcohol-preciptation method from wheat bran koji extract was acted at 40-50°C and pH 4.8-5.8 on the soluble-starch solution in which one of 60 kinds of salts was dissolved.
I. Sodium chloride among the chlorides and all the phosphates have evident accelerating properties, but the degree of acceleration is not always similar, thus the phosphates have accelerating properties which decrease slowly with increasing concentration, while NaCl has powerful accelerating properties at lower concentrations. The accelerating properties of NH4' are remarkable; besides NH4OH, all kinds of ammonium salts have higer accelerating powers than any other salts. The ammoniun phosphate, therefore, is the most effective, showing the concentration of maximum acceleration lower than other phosphates.
II Phosphates, NaCl, and (NH4) 2S04 have little effect on the action of a-amylase and β-amylase, but they have an evident accelerating effect on the action of maltase. So we presumed that the influence of salts on the action of diastase was chiefly the influence on the maltase. But this should be finally justified only after the xperiments with purely isolated β-amylase.
We found that.: he accelerating properties of salts on the diastase were not only caused by the prevention of diastase from the adsorption on the starch corpuscles.
III We examined the fermentation with yeast of the diastatically hydrolyzed starch solutions with added salts described as above.
The NH' has a fairly evident effect to raise the constant fermentation, and the sugar concentration, in the solution and its fermentation are not always corresponding, for instance, the solution hydrolyzed by 0-amylase and maltase only is always more fermentable than that hydrolysed by the total diastase, though the sugar concentration of the former is lower than that of the later.
