水産動物のキチン分解酵素に関する研究-7-クロダイのキチン分解酵素について

概要

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In the previous papers of this series1-7), some properties of the chitinolytic ezyme in some organs of a few species of aquatic animals were reported. In these studies, the amount of oligo-N-acetylamino sugar produced was estimated from that of N-acetylamino sugar liberated by β-glucosidase. In the present study, some properties of the enzyme from the viscera of a sea bream, Acanthopagrus schlegedi, were investigated in the same way as described in the previous papers, except that the oligo sugar was hydrolyzed with HCl. The results obtained are summarized as follows: 1) Heating with 3N-HCl at 100°C for 40 minutes was found to be optimum for the hydrolysis of oligo-N-acetylamino sugar liberated by the chitinolytic enzyme. 2) The stomach of sea bream showed a considerably high activity, whereas the activity of the liver was moderate and the pyloric caeca and intestine little (Table 1). 3) The optimum pH and temperature of the enzyme extracted from the stomach were 3.4-4.0 (Fig. 4) and about 60°C (Fig. 6), respectively. 4) The enzyme was stable between pH 2.5 and 8.0 (Fig. 5). 5) It was resistant for heating at 30-70°C for 20 minutes, but unstable at 80°C (Fig. 7).