| Project/Area Number |
62470149
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
物質生物化学
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| Research Institution | Osaka University |
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Principal Investigator |
IKENAKA Tokuji Faculty of Science, Osaka University, Professor, 理学部, 教授 (20028088)
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| Co-Investigator(Kenkyū-buntansha) |
HARA Saburo Faculty of Science, Osaka University, Associate Professor, 理学部, 助教授 (00028193)
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| Project Period (FY) |
1987 – 1988
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| Project Status |
Completed (Fiscal Year 1988)
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| Budget Amount *help |
¥3,900,000 (Direct Cost: ¥3,900,000)
Fiscal Year 1988: ¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 1987: ¥2,200,000 (Direct Cost: ¥2,200,000)
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| Keywords | Trypsin inhibitor / Inhibitory mechanism / アミノ酸残基の化学的変換 |
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| Research Abstract |
Trypsin inhibitors could be reconstituted by mixing the protein moieties and the peptide moieties (from position 64 to position 84) separated from two enzymatically modified soybean trypsin inhibitors by the mutual exchange. A reconstituted inhibitor which has tyrosine at position 62 and histidine at position 71 showed the highest inhibitory activity with Ki value of approximately 10^<-10> M. An inhibitor having phenylalanine and asparagine at positions 62 and 71, respectively, showed the weakest inhibitory activity with Ki value of about 10^<-8> M. Inhibitors possessing either tyrosine at position 62 or histidine at position 71 had Ki value of about 10^<-9> M. Other inhibitors were reconstituted by mixing the protein moieties and synthetic peptides. The replacements of serine residue at position 74 to arginine, and methionine at position 84 to methionine sulfoxide did not affect on Ki values, indicating that they are not concerned directly in contacting with trypsin. No inhibitory activity was observed when the protein moieties were mixed with a synthetic peptide lacking His(71), Pro(72) and Leu(73) residues.
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