The experiments described below deal with the proteolytic activity shown by liver extract of cuttle-fish. The results are summarized as follows:
1) As shown in Fig. 1, it was found that the optimal pH of enzymatic activity for digestion of casein or hemoglobin by liver extract and the value of activity which was shown at the same pH changed with the time of reaction.
2) The relationship between the degree of casein hydrolysis and the time of reaction was shown in Fig. 2. From the results it is evident that the activity is different between the initial stage (0-40 min.) and the subsequent one, the activity in the latter being 1.7 times stronger than that in the former.
3) From the results described in this paper and previous one1) it may be concluded that the desirable pH value is about 5 and temperature is 50°C for autlyzation of cuttle-fish viscera (Fig. 3 and Table 1).