Incorporation and distribution of epoxyeicosatrienoic acids into cellular phospholipids.
Incorporation and distribution of epoxyeicosatrienoic acids into cellular phospholipids.
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DOI：
10.1016/s0021-9258(19)50579-8
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发表时间：
1992-02
期刊：
影响因子：
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通讯作者：
K. Bernstrom;K. Kayganich;R. Murphy;F. Fitzpatrick
中科院分区：
文献类型：
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作者：
K. Bernstrom;K. Kayganich;R. Murphy;F. Fitzpatrick
来源于细胞色素P-450单加氧酶的环氧二十碳三烯酸的不同区域异构体容易酯化成肥大细胞瘤细胞的磷脂。14，15-环氧二十碳三烯酸的掺入是浓度依赖性的，Km = 1.1 μ M，Vmax = 36 pmol/min/10（7）个细胞。半最大掺入发生在30分钟内，达到470 pmol/10（6）个细胞的稳态浓度。这略低于花生四烯酸（665 pmol/10（6）细胞）或5-羟基二十碳四烯酸（554 pmol/10（6）细胞）的值。14，15-epoxyeicosatrienoic acid的分布是优先的顺序磷脂酰乙醇胺大于磷脂酰胆碱大于磷脂酰肌醇大于磷脂酰丝氨酸远远大于中性脂质加上脂肪酸。这与主要分布于磷脂酰胆碱中的5（S）-羟基二十碳四烯酸形成对比。快速原子轰击/串联质谱法有助于鉴定含有环氧二十碳三烯酸的分子种类，而不依赖于放射性同位素。在sn-1位具有16：1或18：2或18：0酰基的磷脂酰乙醇胺缩醛磷脂和在sn-1位具有16：0烷基醚或酰基的磷脂酰胆碱掺入了所有可能的环氧二十碳三烯酸区域异构体。在基础条件下，细胞缓慢消除14，15-顺式-环氧二十碳三烯酸，半衰期为34.9 +/- 7 h。用钙离子载体A23187刺激的细胞迅速消除14，15-环氧二十碳三烯酸。值得注意的是，其从磷脂酰胆碱和磷脂酰肌醇的释放速率超过花生四烯酸。一种辅酶A-非依赖性转酰酶也能催化氧化二十碳三烯酸从肥大细胞瘤细胞膜转移到1-棕榈酰-2-溶血磷脂酰胆碱。环氧二十碳三烯酸的细胞掺入、释放和分布是独特的，与大多数其他类二十碳三烯酸形成对比，表明这些化合物可能具有autocoid和nonautocoid功能。
The different regioisomers of epoxyeicosatrienoic acids derived from cytochrome P-450 monooxygenase are readily esterified into phospholipids of mastocytoma cells. Incorporation of 14,15-epoxyeicosatrienoic acid was concentration-dependent, with Km = 1.1 microM and Vmax = 36 pmol/min/10(7) cells. Half-maximal incorporation occurred in 30 min, reaching a steady-state concentration of 470 pmol/10(6) cells. This was slightly lower than the values for arachidonic acid (665 pmol/10(6) cells) or 5-hydroxyeicosatetraenoic acid (554 pmol/10(6) cells). The distribution of 14,15-epoxyeicosatrienoic acid was preferential in the order phosphatidylethanolamine greater than phosphatidylcholine greater than phosphatidylinositol greater than phosphatidyl serine much greater than neutral lipids plus fatty acids. This contrasted with 5(S)-hydroxyeicosatetraenoic acid, which was distributed primarily into phosphatidylcholine. Fast atom bombardment/tandem mass spectrometry facilitated identification of molecular species containing epoxyeicosatrienoic acids without relying on radioisotopes. Phosphatidylethanolamine plasmalogens with 16:1 or 18:2 at the sn-1 position, or an 18:0 acyl group, and phosphatidylcholine with 16:0 alkyl ether or an acyl group at the sn-1 position incorporated all possible epoxyeicosatrienoic acid regioisomers. Under basal conditions, cells eliminated 14,15-cis-epoxyeicosatrienoic acid slowly with a half-life of 34.9 +/- 7 h. Cells stimulated with calcium ionophore A23187 eliminated 14,15-epoxyeicosatrienoic acid rapidly. It was notable that its rate of release from phosphatidylcholine and phosphatidylinositol exceeded that for arachidonic acid. A coenzyme A-independent transacylase also catalyzed the transfer of epoxyeicosatrienoic acids from mastocytoma cell membranes into 1-palmitoyl-2-lysophosphatidylcholine. The cellular incorporation, release, and distribution of epoxyeicosatrienoic acids is distinctive and contrasts with most other eicosanoids, suggesting that these compounds may have both autocoid and nonautocoid functions.