Lysosomal Thiol Proteinase in the Tadpole Tail of Rana catesbeiana: Some Properties and Changes in the Activity during Metamorphosis

概要

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The tadpole tail of Rana catesbeiana contains a thiol proteinase and cathepsin D (EC 3.4.23.5) which can hydrolyze hemoglobin at acidic pH. The thiol proteinase was activated 1.7-times by cysteine and showed maximal activities at pH3.2. The activity was inhibited by leupeptin, antipain and chymostatin, but not by pepstatin. In contrast, cathepsin D wasinhibited only by pepstatin. BY use of leupeptin and pepstatin, the two hemoglobin degrading enzymes in the tail were assayed separately, and the changes in their activities during metamorphosis were estimated. The activity of the thiol proteinase per tail increased 3.8-fold and that of cathepsin D 1.8-fold in the regressing tail. Subcellular fractionation of the tail suggested a lysosomal origin for the thiol proteinase as well as cathepsin D. The thiol proteinase was thougut to be a cathepsin B (EC 3.422.1)-like enzyme, and may play a role in the degradation of tail during metamorphosis.
社団法人日本動物学会の論文
1983-06-25