| Project/Area Number |
10044224
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| Research Category |
Grant-in-Aid for Scientific Research (A).
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Biological pharmacy
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| Research Institution | HOKKAIDO UNIVERSITY |
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Principal Investigator |
KAMATAKL Tetsuya Grad. School of Pharm. Sci., Hokkaido Univ., Prof., 大学院・薬学研究科, 教授 (00009177)
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| Co-Investigator(Kenkyū-buntansha) |
ARIYOSHI Noritaka Grad. School of Pharm. Sci., Hokkaido Univ., Asso. Prof., 大学院・薬学研究科, 助教授 (00243957)
TAKAHASHI Yoshiki Grad. School of Pharm. Sci., Hokkaido Univ., Inst., 大学院・薬学研究科, 助手 (80292019)
NAKAYAMA Kazuo Grad. School of Pharm. Sci., Hokkaido Univ., Inst., 大学院・薬学研究科, 助手 (20261323)
UJJIN Pailin チュラロンコン大学, 臨床検査医学部, 部長
FUJITA Ken-ichi Grad. School of Pharm. Sci., Hokkaido Univ., Inst., 大学院・薬学研究科, 助手 (60281820)
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| Project Period (FY) |
1999 – 2000
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| Keywords | trimethylamine / FMO / genetic polymorphism / genetic disease / gene therapy / heterologous expression / human genome / gene analysis |
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| Research Abstract |
We examined the metabolism of trimethylamine (TMA) in human liver microsomes. The kinetic parameters of TMA N-oxidation showed the apparent Km and Vmax values of 45.9 μM and 2.24 nmol/min/mg protein, respectively. The N-oxidation of TMA was inhibited by the known flavin-containing monooxygenase (FMO) inhibitors such as methimazole and heat treatment, but not by SKF-525A, cytochrome P450 inhibitor. To identify the FMO form responsible for the N-oxidation of TMA, the TMA N-oxidase activities of human FMO1, FMO3 and FMO5 expressed in E, coli were measured. FMO5 showed no TMA N-oxidase activity. The Vmax/Km value for FMO3 was about 355 times higher than that for FMO1 when the kinetic parameters of TMA N-oxidation was examined. We analyzed the FMO3 gene of Thai possible patients with fish-odor syndrome. A novel mutation, a single base substitution from G to A at the position of 265 (G265A), was identified in exon 3 of two patients. The mutated FMO3 protein with an amino acid substitution from valine to isoleucine at residue 58 (V58I) exhibited the reduced TMA N-oxidase activity when it was expressed in Salmonella. We conclude that FMO3 gene with this mutation produce the FMO protein that has reduced catalytic activities.
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