ATP‐dependent leukotriene export from mastocytoma cells

[摘要]

The biosynthesis of leukotrienes (LT) C₄ and B₄ is followed by an export of these mediators into the extracellular space. This transport was characterized using plasma membrane vesicles prepared from mastocytoma cells and identified as an ATP-dependent primary active process. The apparent K_m -values were 110 nM for LTC₄ and 48 μM for ATP. The transport rate was highest for LTC₄, whereas LTD₄, LTE₄, and N-acetyl-LTE₄ were transported with relative rates of 31, 12 and 8%, respectively, at a concentation of 10nM. LTB₄ transport was also dependent on ATP, LTC₄ transport with inhibited by LTD₄ receptor antagonists (IC₁₀ = 1.0 μM for MK-571 and 1.3 μM for LY245769) and by the inhibitor of leukotriene biosynthesis MK-886 (IC₁₀ = 1.8 μM). The ATP-dependent export carrier for leukotrienes in leukotriene-synthesizing cells represents a novel member of the family of ATP-dependent exit pumps.

[学科分类] 生物化学/生物物理

[关键词] ATP-dependent transport;Mastocytoma cells;Leukotriene export;LT;leukotriene;LTE4NAc;N-acetyl-leukotriene E4;ω-OH-LTB4;ω-hydroxy leukotriene B4;ω-COOH-LTB4;ω-carboxy leukotriene B4;PG;prostaglandin;DNP-SG;S-(2;4-dinitrophenyl)-glutathione;MK-886;3-[1-(4-chlorobenzyl)-3-t-butyl-thio-5-isopropylindol-2-yl]-2;2-dimethyl-propanoic acid;MK-571;3-(3-(2-(7-chloro-2-quinolinyl)ethenyl)phenyl)((S-dimethyl amino-3-oxopropyl)thio)propanoic acid;LY245769;(1S;2R)-5-(3-[1-hydroxy-15;15;15-trifluoro-2-(2-1H-tetrazol-5-ylethylthio)-pentadeca-3(E);5(Z)-dienyl]phenyl)-1H-tetrazole