| Project/Area Number |
06454179
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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 |
Pathological medical chemistry
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| Research Institution | Tokushima University |
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Principal Investigator |
YAMAMOTO Shozo Department of Biochemistry, University of Tokushima, School of Medicine Professor, 医学部, 教授 (50025607)
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| Co-Investigator(Kenkyū-buntansha) |
SUZUKI Hiroshi Department of Biochemistry, University of Tokushima, School of Medicine Research, 医学部, 助手 (80253194)
HAYASHI Yoko Department of Biochemistry, University of Tokushima, School of Medicine Research, 医学部, 助手 (60035441)
UEDA Natsuo Department of Biochemistry, University of Tokushima, School of Medicine Associat, 医学部, 助教授 (20193807)
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| Project Period (FY) |
1994 – 1995
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| Project Status |
Completed (Fiscal Year 1995)
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| Budget Amount *help |
¥7,100,000 (Direct Cost: ¥7,100,000)
Fiscal Year 1995: ¥2,800,000 (Direct Cost: ¥2,800,000)
Fiscal Year 1994: ¥4,300,000 (Direct Cost: ¥4,300,000)
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| Keywords | Arachidonic acid / Prostaglandin / Anadamide / Lipoxygenase / 12-Lipoxygenase / Cyclooxygenase-1 / Cyclooxygenase-2 / Baculovirus |
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| Research Abstract |
Bioactive eicosanoids such as prostaglandins, thromboxanes and leukotrienes are produced from arachidonic acid which is the substrate of various lipoxygenases and cyclooxygenases. We studied the catalytic properties and the regulatory mechanism of gene expression of these enzymes with special reference to their isozymes.
1)Selective inhibitor of 5-lipoxygenase : An antioxidant YT-18 caused a lag phase prior to initiation of 5-lipoxygenase reaction. This effect was specific for 5-lipoxygenase.
2)Suicide inactivation of 12-lipoxygenase : Leukocyte 12-lipoxygenase is a typical suicide enzyme.The enzymeproduced 15-hydroperoxy acid as a minor product from arachidonic acid, which was further transformed to 14,15-epoxy acid by the same enzyme. Several lines of evidence suggested the inactivation of the enzyme which incorporated the 14,15-epoxy acid. Platelet 12-lipoxygenase produced little amount of 15-hydroperoxy acid and was scarcely suicide-inactivated.
3)Anandamide as substrate of leukocyte 12-lipoxygenase : Anandamide(arachidonylethanolamine)is an endogenous ligand of cannabinoid receptor. The compound was oxygenated by leukocyte 12-lipoxygenase, but was a poor substrate of platelet enzyme. The 12-oxygenated anandamide was biologically almost inactive.
Transcriptional regulation of 12-lipoxygenase gene : The promoter region of platelet 12-lipoxygenase gene was examined, and NFkB element(-539 to -530bp)was proposed to negatively regulate the transcription of the enzyme gene.
Induction of cyclooxygenase-1 : Human megakaryoblastic CMK cells were treated wtih TPA,which induced cyclooxygenase-1 enzyme.
Transcriptional regulation of cyclooxygenase-2 : When murine osteoblastic MC3T3-E1 cells were treated with TNFalpha, cyclooxygenase-2 was induced. Several lines of experimented findings suggested a regulatory role of NFkB and NF-IL6 in the transcription of cyclooxygenase-2.
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