イカ内臟の生化学的研究-VI : スルメイカ肝臟蛋白分解酵素の二三の性質について

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概要

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• In the previous paper1), it was reported that the optimal pH of casein digestion by the extract of cuttle-fish liver lie in the range of 5.0-6.0 and at 2.5. Two kinds of proteinases with different pH optima at 5.0-6.0 and 2.5 respectively seem to be existed in the liver at least. Accordingly, this work was undertaken to see several characteristic properties of these proteinases. Both the proteinase with the optimal pH at 5.0-6.0 and the proteinase with the optimal pH at 2.5 were found to be activated by such reducing agents as NaCN, cysteine, ascorbic acid, and glutathione (Table 1). On the other hand, these actions were inhibited by metallic ions, such as Mn…, Mg…, Co…, Cu…, and Zn…, and by such thiol reagents as monoiodoacetate, and p-chloromercuribenzoate (PCMB). (Tables 2 and 3) However, it was observed that there are some differences in the effects of activators or inhibitors on the activities of these proteinases; in the former, its action is more powerfully activated by the reducing agents than that in the latter and is more strongly inhibited by the metal ions and the thiol reagents. As shown in Fig. 2, it was found that the inhibitions by PCMB are readily reversed by the addition of cysteine in the both. From the results, it may be concluded that cuttle-fish liver contains two kinds of cathepsinlike enzymes of which natures resemble each other, and each proteinase possesses sulfhydryl radical as one of the active centers.

• 公益社団法人 日本水産学会の論文

著者

• 高橋 喬

  三重県立大学水産学部

関連論文

• イカ内臟の生化学的研究-VI : スルメイカ肝臟蛋白分解酵素の二三の性質について
• イカの利用に関する研究-III : スルメイカ魚体の各部分比およびその組成の季節的変化について
• イカ内臓の生化学的研究-V : 澱粉分解酵素およびエステル分解酵素について
• 柔魚内臓の生化学的研究-II : 肝臟エキスの窒素化合物について
• 柔魚内臓の生化学的研究-I : 無機成分について
• ブリ若年魚における餌料成分の消化率
• 後唾腺の蛋白消化酵素の存在確認試験 (マダコ後唾腺蛋白分解酵素の消化への関与に関する研究-1,2-)

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