| Project/Area Number |
61560139
|
|---|
| Research Category |
Grant-in-Aid for General Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Research Field |
製造化学・食品
|
|---|
| Research Institution | Nagoya University |
|---|
Principal Investigator |
KAWAKISHI Shunro Professor, Nagoya University, School of Agriculture, 農学部, 教授 (50023445)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
HAYASHI Tateki Assistant Professor, Nagoya University, School of Agriculture, 農学部, 助手 (90023473)
|
|---|
| Project Period (FY) |
1986 – 1987
|
| Project Status |
Completed (Fiscal Year 1987)
|
| Budget Amount *help |
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1987: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1986: ¥1,400,000 (Direct Cost: ¥1,400,000)
|
|---|
| Keywords | Active Oxygen / Ascorbic Acid-Copper Ion System / Superoxide / Hydroxyl Radical / Depolymerization of Polysaccharides / Depolymerization of Proteins / ヒスチジンの酸化分解 / 過酸化水素-銅イオン系 / ヒスチジンの酸化 / オキソヒスチジンの生成 |
|---|
| Research Abstract |
1. Oxidative Degradation of Polysaccharides with Oxygen Radicals.
Polysaccharides were markedly depolymerized by the action of ascorbic acid-cupric ion (AsA-Cu) system at room temperature form MW 10^5 < to 10^4. This oxidation reaction was considarably accelerated on the polysaccharide having a molecular weight above 5 x 10^5. The polysaccharide linked by (1->6) bond exhibited a high reactivity compared with the (1->4) linked one, because the former have a strong affinity for metal ions than the latter. To make clear the mechanism of above mentioned oxidative cleavage on polysaccharides, maltose and isomaltose were used as models. It was assumed that the glycosidic linkage would be cleaved through unstable carbonyl compounds produced from sugar residues by the oxidative action of hydroxyl radical.
2. Oxidative Damages of Protein with Oxygen Radicals.
Bovine serum albumine (BSA) was oxidatively degraded to polypeptide fractions with oxigen radicals produced from Asa-Cu system, as detected by the HPLC and SDS-PAGE. Histidine and tryptophan residues in protein decreased significantly, but other amino acids didn't change at all by amino acid analyses of oxidized BSA. Moreover, same site-specific oxidation at histidine residue was also observed on histidine containing peptides.
3. Oxidative Degradation of Histidine.
By using of N-benzoylhistidine, and oxidative degradation on its imidazole ring was investigated in detail. Eight produnts were isolated by HPLC from the reaction mixture of N-benzoyl histidine and ascorbic acid-Cu system at room temperature and their structures were determined. From these results, it is probable that histidine is attacked with oxygen radical to give 2-oxo derivative which is degraded by repeated action of oxygen radical to aspartic acid finally via some intermediates.
|
