In order to experiment the effects of low and high temperature upon the enzyme activity, the author used papayotin and taka-diastase and he came to the following conclusions: 1) In refregirathing experiment in 0℃, -18℃, -48℃ and -52℃, optimum pH in the activity of papayotin and taka-diastase is found 4.6~5.0. 2) The activity of papayotin and taka-diastase is not reduced even when the enzyme is iced in 0℃ for ten days. 3) After refregirating just papayotin powder in -18℃ and working it on gelatin solution, the enzyme activity increases; and on the contrary, after refregirating gelatin solution in -18℃ and working it on the papayotin powder, the enzyme activity decreases; and lastly, it is found out that the influence of refregirating on the enzyme activity is stronger when refregirated in -18℃ for two hours han only thirty minutes in the same degree of temperature. In the experiment used taka-diastase, when either just enzyme powder, or starch solution, or mixed solution of enzyme powder and buffer solution or of enzyme powder, starch solution and buffer solution are iced in -18℃ the enzyme activity has tendency to increase a little. In case of refregirating just starch solution, the increase of taka-diastase is seen very clearly; and two hours' refregirating in -18℃ is much stronger in activity of increase than of thirty minutes. 4) In the experiment in -48℃, papayotin iced for thirty minutes and worked upon gelatin solution shows a little increase in its activity; but in the case when just gelatin solution is iced, it is not clear of any influence of refregirating. In the same experiment, when either or taka-diastase or starch solution or mixed solution of these two is iced in -48℃, the activity of taka-diastase begins to increase a little and stronger increase is found always in just starch solution which is iced for two hours rather than thirty minutes. 5) In the experiment is -52℃, just papayotin is iced and its activity with a little increase is more clealy shown in thirty minutes' refregirating rather than that of one or two hours. Either just starch solution or mixed solution of taka-diastase and starch solution is iced, the influence of refregirating on the activity of papayotin is not clear. In the experiment used take-diastase, its activity increases when just starch solution is iced, and on the other hand, the influence of refregirating upon the activity is not clear when either of taka-diastase or mixed solution of taka-diastase and starch solution is iced. 6) In short, it is found out that the papayotin in the decomposition of gelatin increases when the papayotin powder is iced; and taka-diastase in the decomposition of starch increases when the starch solution is iced: the former is the increase of papayotin based on the disaggregation of colloidal granule (F, Nord) and the latter is that the activity of taka-diastase could be made easier by refregirating starch solution and making granule into smaller pieces. 7) In heating take-diastase solution in 70℃ for thirty minutes, the influence of heat upon the activity of taka-diastase is not shown; but the slight decrease of activity would be seen in case of heating in 80℃ for thirty minutes. 8) In heating taka-diastase solution in 100℃ for thirty minutes, the activity is gone completely which will never come back even when taka-diastase is iced in -18℃.