2003 Fiscal Year Final Research Report Summary
The novel function of a key enzyme regulating tryptophan-NAD metabolism
| Project/Area Number |
13660118
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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 |
食品科学・栄養科学
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| Research Institution | Chiba University |
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Principal Investigator |
EGASHIRA Yukari Chiba University, Faculty of Horticulture, Associate Professor, 園芸学部, 助教授 (80213528)
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| Co-Investigator(Kenkyū-buntansha) |
SANADA Hiroo Chiba University, Faculty of Horticulture, Professor, 園芸学部, 教授 (60196293)
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| Project Period (FY) |
2001 – 2003
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| Keywords | tryptophan / niacin / immunity / ACMSD / rat / quinolinate / picolinate / linoleic acid |
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| Research Abstract |
Picolinate has been implicated in immune system in vitro experiments. On the other hand, quinolinate is a potent endogenous excitotoxin of neuronal cells. α-amino-β-carboxymuconate-ε-semialdehyde decarboxylase (ACMSD ; EC 4.1.1.45) is one of the important enzymes regulating tryptophan-niacin metabolism. ACMSD seems to be able to influence directly the production of picolinate and quinolinate. In this study, we investigated the effect of acute immune stimulation on ACMSD activity and mRNA expression in rats. ACMSD mRNA was expressed in the liver and kidney, but not in the brain, lung, spleen and thymus by RT-PCR in control and LPS-treated groups. There were no significant difference between control and LPS treated rats in ACMSD activity and mRNA. Moreover we measured the tryptophan catabolite quinolinic acid level in rats fed on linoleic acid. In rats fed with 10 or 20% linoleic acid diet, ACMSD mRNA in the liver was strongly suppressed and serum quinolinic acid was significantly increased as compared with the rats fed on a fat-free diet. These results suggest that there is an inverse relationship between ACMSD activity and the production of quinolinic acid converted from tryptophan.
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