Bombyx acid cysteine proteinase |
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Authors: | SUSUMU Y. TAKAHASHI YOSHIMI YAMAMOTO XIAOFAN ZHAO SHOJI WATABE |
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Affiliation: | 1. Laboratory of Biochemistry and Radiation Biology , College of Agriculture, Yamaguchi University , Yamaguchi 753, Japan Phone: +81 (839) 33-5909 Fax: +81 (839) 33-5909;2. Department of Biology , Shandong University , Jinan, Shandong, Peoples Republic of China;3. Radioisotopes Laboratory , Yamaguchi University , Yamaguchi, 753, Japan |
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Abstract: | Summary Three kinds of yolk proteins (vitellin, egg-specific protein and 30 k-proteins) are found in silkmoth eggs and have been well characterized. Essentially these proteins are considered to be amino acid reserves for developing embryos. Since at an early stage of egg development the cysteine proteinase accounts for the majority of the total proteinase activity, it may be involved in the degradation of yolk proteins. The enzyme is stored in the eggs as an inactive pro-form, indicating that the activation of the enzyme might be one of the key steps in yolk protein degradation. To investigate at the molecular level how yolk proteins degradation takes place, we have studied Bombyx acid cysteine proteinase (BCP) during an early period of embryonic development. We summarize how proteinases are regulated and are involved in the degradation of Bombyx yolk proteins during embryogenesis. These will be discussed mainly in light of recent results obtained from eggs of the silkmoth, Bombyx mori. |
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Keywords: | BCP pro-cysteine proteinase yolk protein degradation |
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