Studies on the biosynthetic mechanism of platelet-activating factor and its physiological significance in alveolar macrophages
| Project/Area Number |
62480425
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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 |
Biological pharmacy
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| Research Institution | Faculty of Pharmaceutical Sciences, Teikyo University |
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Principal Investigator |
WAKU Keizo Fac. Pharm. Sci., Teikyo University, Professor, 薬学部, 教授 (90013854)
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| Co-Investigator(Kenkyū-buntansha) |
SUGIURA Takayuki Fac. Pharm. Sci., Teikyo University, Research Associate, 薬学部, 助手 (40130009)
NAKAGAWA Yasuhito Fac. Pharm. Sci., Teikyo University, Lecturer, 薬学部, 講師 (00119603)
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| Project Period (FY) |
1987 – 1988
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| Project Status |
Completed (Fiscal Year 1988)
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| Budget Amount *help |
¥6,500,000 (Direct Cost: ¥6,500,000)
Fiscal Year 1988: ¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 1987: ¥5,000,000 (Direct Cost: ¥5,000,000)
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| Keywords | Alkylether Phospholipid / Macrophage / Platelet-activating Factor / Arachidonic Acid / Transacylase / アセチルトランスフェラーゼ / アルキル型リン脂質 |
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| Research Abstract |
1. Studies on the acylation mechanism of alkylether phospholipids. We studied the acylation mechanism of 1-alkyl-glycerophosphocholine (GPC), using 1-alkyl-GPC as an acceptor and diacyl-GPC, including ^<14>C-arachidonic acid at the 2-position, as an acyl donor, by rabbit alveolar macrophage microsomes. This transacylation reaction does not need CoA, ATP or Mg^<2+>. C-20 fatty acids, especially arachidonic acid (20:4) and docosahexaenoic acid (22:6) are the good substrates for this enzymatic reaction.
2. Release of arachidonic acid from alkylether phospholipids and incorporation of acetyl residue into 1-alkyl-GPC. Lyso platelet-activating factor (lyso PAF, 1-alkyl-GPC) produced by phospholipase A_2 action on ether choline glycerophospholipid (CGP) was acetylated or acylated by acetyltransferase or transacylase, competitively. The specific activity of acetyltransferase was 474 pmole/min/10^6cell lysate (acetylCoA; 100 m) and increased by 2-3 times on the cell stimulation with A23187. That of transacylase was 98 pmole/min/10^6cell lysate and significant increase of the activity was not observed on cell stimulation. on the other hand, the acetyltransferase activity was quite dependent on the concentration of acetyl-CoA in the case of no addition of exogenous acetyl-CoA. Therefore, in this case, lyso PAF seemed to be acylated mainly by transacylase with 20:4, rather than by acetyltransferase. The localization of these enzymes or substrates in cells shoud be studied in the next step.
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Report
(3 results)
Research Products
(16 results)
