2000 Fiscal Year Final Research Report Summary
The studies on the sugar chain structures of rat cathepsin J (C) and its functions.
| Project/Area Number |
11680607
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Structural biochemistry
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| Research Institution | The University of Tokushima |
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Principal Investigator |
TOWATARI Takae Institute for Enzyme Research, The University of Tokushima, Associate professor, 分子酵素学研究センター, 助教授 (60108876)
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| Co-Investigator(Kenkyū-buntansha) |
INOUE Masahiro Institute for Enzyme Research, The University of Tokushima, Assistant professor, 分子酵素学研究センター, 助手 (00232562)
KIDO Hiroshi Institute for Enzyme Research, The University of Tokushima, Professor, 分子酵素学研究センター, 教授 (50144978)
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| Project Period (FY) |
1999 – 2000
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| Keywords | Cathepsin J / Cathepsin C / Lysosome / High-mannose-type / Conplex-type / Propeptide / Protease |
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| Research Abstract |
We showed in 1992 that an enzyme previously termed cathepsin J is identical to cathepsin C (dipeptidyl peptidase 1) a lysosomal cysteine protease found predominantly in myelomonocytic cells, cytotoxic T-cellsand mast cells. Cathepsin J (C) has been found to participate in the activation of proenzymes and to be implicated in several pathological events. We also reported that purified cathepsin J (C) consists of propeptide and mature cathepsin J (C) processed as two chain form containing sialic acids in its sugar chains. In this study, the sugar structures of purified rat cathepsin J (C) were investigated by means of the endoglycosidase digestion and pyridylamination method to elucidate its structure and function interrelationships. The sensitivities of the propeptide and the heavy chain of mature form to digestion of glycopeptidase F and Endo H showed that the sugar chains of the propeptide are high mannosetype and those of the heavy chain are complex-type. Furthermore, the sugar chains released from purified rat cathepsin J (C) upon glycopeptidase F digestion were tagged with 2-aminopyridine at their reducing ends , and analyzed by ion-exchange, normal-phase and reversed-phase chromatographies on HPLC systems. Our results indicated that 40% of the sugar chains of purified rat cathepsin J (C) were high mannose-type, having four to seven mannose residues. Thirteen percent of the sugar chains were complex-type having two branches linked to sialic acid. Seven percent were an oligomannose-type having three mannose residues derived from complex-type sugar chains. In addition, some hybrid-type sugar chains were also detected. We propose that for the quarternary structure of rat cathepsin J (C), its propeptides are located internally and the heavy chains of mature form are located externally. Consequentially sugar chains of propeptides are more resistant to lysosomal enzymes than those of the heavy chains.
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