1988 Fiscal Year Final Research Report Summary
Photochemistry of cationic synthetic polyamino acid -dye systems
| Project/Area Number |
61490014
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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 |
広領域
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| Research Institution | Shinshu University |
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Principal Investigator |
YAMAMOTO Hiroyuki Shinshu Univ., Fac. of Textile Sci. & Tech., Assoc. prof., 繊維学部, 助教授 (60021151)
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| Co-Investigator(Kenkyū-buntansha) |
INOUYE Katsuhiko Shinshu Univ., Fac. of Textile Sci. & Tech., Instructor, 繊維学部, 助手 (30092860)
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| Project Period (FY) |
1986 – 1988
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| Keywords | Photochromic polymaino acids / Azo aromatic polypeptides / Cationic peptides / Photoisomerization / Synthesis / Circular dichroism / 円偏光二色性 / 光溶解度 |
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| Research Abstract |
Photochromic polypeptides represent interesting systems because of their relevance to the photoregulation in biological processes and seem to have promise as photosensitive polymeric materials. Currently considerable knowledge is available regarding the spectral and photochromic properties of various neutral and anionic polypeptides. However, little is known about cationic azo aromatic polypeptides. In this project we studied the synthesis and reversible photochromic properties of cationic azo aromatic amino acids (lysine and its lower homologs), oligopeptides (arginine peptide), and polypeptides (alpha-polylysine and its lower homologs, and -polylysine), together with cationic vinyl polymers (polyvinylamine and polyallylamine).
The photochemical properties of the azo aromatic compounds described above was investigated by absorption, fluorescence, and circular dichroism spectroscopy in solvents such as hexafluoro-2-propanol (HFIP). When chiral, the photochromism of the dichroic band in the visible wavelength region was mostly reversible as a function of irradiation time at different wavelengths due to the trans-cis photoisomerization of the azo aromatic moieties. The negative dichroic bands below 240 nm, the backbone conformations of the cationic azo aromatic polypeptides with longer side chains take an alpha-helix, while those with shorter a beta-structure. The photochemical behaviors of the beta-structure azo aromatic polypeptides exhibit the characteristic reversible dichroic photochromism. The photo-stimulated solubility changes due to the different dipole moments of two azo geometric conformers were examined in such mixed solvents as HFIP-water.
Since cationic azo aromatic polylysine homologs may have promise as photoresponsive systems, we extent our study to synthesize the natural phytochrome model peptides and to prepare the photosensory systems.
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