| Project/Area Number |
10650885
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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 |
高分子構造・物性(含繊維)
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| Research Institution | Nagoya Institute of Technology |
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Principal Investigator |
NAKANISHI Eiji Nagoya Institute of Technology, Department of Engineering, Professor, 工学部, 教授 (10180316)
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| Co-Investigator(Kenkyū-buntansha) |
岡本 茂 名古屋工業大学, 工学部, 助手 (50262944)
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| Project Period (FY) |
1998 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥2,500,000 (Direct Cost: ¥2,500,000)
Fiscal Year 1999: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1998: ¥2,100,000 (Direct Cost: ¥2,100,000)
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| Keywords | TFA treatment / Tryptophan / color change / anionic drugs / polypeptide / microsphere / 色変化 |
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| Research Abstract |
We have reported that the coloration phenomenon of L-tryptophan(Trp) treated with trifluoroacetic acid (TFA) was observed with varying pH, i. e., from yellow to red. In order to elucidate the coloration mechanism, the colored compounds were fractionated and investigated. It was found that Trp forms the yellow compound consisting of a tricyclic structure, and that the change in color with the variation of pH is due to the dissociation of the nitrogen atom in the indole ring. The Trp residues within copoly (L-glutamic acid-co-Trp) (GAT) was also found to form the same tricyclic structure by the treatment with TFA and to show the reversible color change from yellow (above pH 8.0) to red (below pH 7.0) through the positive-dissociation at the neutral pH region. The interaction between TFA-treatment GAT (GAT-T) and anionic molecules was investigated by VIS and fluorescence spectrophotometry. The Trp residues within GAT-T were found to electrostatically interact with bulky anionic drugs such as watrfarin (Wf), clofibric acid (Cf) and phenylbutazone (Pb) besides the hydrophobic interaction, resulting in the color change from red to yellow. Release behavior of the anionic drugs from GAT-T microspheres (Ms) was also investigated. The amount and the retention time of the bound anionic drugs in the GAT-T Ms were found to be superior to those for untreatment GAT Ms. Moreover, GAT-T interacts strongly with the anionic drugs in the order of Cf > Pb > Wf. This originates in the acidity of the anionic drugs used.
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