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Journal of Biomedicine and Biotechnology
Volume 2009, Article ID 746289, 6 pages
Research Article

Expression and Purification of Active Recombinant Cathepsin C (Dipeptidyl Aminopeptidase I) of Kuruma Prawn Marsupenaeus japonicus in Insect Cells

1E-Institute of Shanghai Universities (EISU) Aquaculture Division and Key Laboratory of Aquatic Genetic Resources and Aquacultural Ecology, College of Life Science, Shanghai Ocean University, 999 Hucheng Huan Road, Shanghai 201306, China
2Fisheries Research Agency, National Research Institute of Aquaculture, 422-1 Nakatsuhamaura, Minami-ise, Mie 516-0193, Japan

Received 11 March 2009; Accepted 19 June 2009

Academic Editor: Ernest S. Chang

Copyright © 2009 Gao-Feng Qiu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Cathepsin C (CTSC) is a lysosomal cysteine protease belonging to the papain superfamily. Our previous study showed that CTSC precursor (zymogen) is localized exclusively in cortical rods (CRs) of mature oocyte in the kuruma prawn Marsupenaeus japonicus, suggesting that CTSC might have roles on regulating release and/or formation of a jelly layer. In this study, enzymically active CTSC of the kuruma prawn was prepared by recombinant expression in the High Five insect cell line. The recombinant enzyme with a polyhistidine tag at its C-terminus was considered to be initially secreted into the culture medium as an inactive form of zymogen, because Western blot with anti-CTSC antibody detected a 51 kDa protein corresponding to CTSC precursor. After purification by affinity chromatography on nickel-iminodiacetic acid resin, the enzyme displayed three forms of 51, 31, and 30 kDa polypeptides. All of the forms can be recognized by antiserum raised against C-terminal polyhistidine tag, indicating that the 31 and 30 kDa forms were generated from 51 kDa polypeptide by removal of a portion of the N-terminus of propeptide. Following activation at pH 5.5 and for 40 hours under native conditions, the recombinant CTSC (rCTSC) exhibited increased activity against the synthetic substrate Gly-Phe- -naphthylamide and optimal pH at around 5. The purified rCTSC will be useful for further characterization of its exact physiological role on CRs release and/or formation of a jelly layer in kuruma prawn.