Luquain C, Dolmazon R, Enderlin J M, Laugier C, Lagarde M, Pageaux J F
Laboratoire de Biochimie et Pharmacologie, INSA Lyon, INSERM U352, France.
Biochem J. 2000 Nov 1;351 Pt 3(Pt 3):795-804.
In rat uterine stromal cells (U(III) cells), docosahexaenoic acid (DHA) was esterified extensively in alkenylacyl-glycerophosphoethanolamine and in an unknown phospholipid accounting for only 0.7% of the total phospholipid. The latter was identified as a bis(monoacylglycerol) phosphate (BMP) using MS. Incorporation studies using C(18:3)n-3 and C(20:5)n-3 demonstrated that BMP had a high specificity to incorporate DHA and C(22) polyunsaturated fatty acids of the (n-3) series. By contrast, polyunsaturated fatty acids of the (n-6) series were never incorporated into BMP. Incubation of U(III) cells with 5 microM DHA for 24 h increased the DHA content of BMP from 36 to 71% of the total acyl chains. [(3)H]DHA-labelled BMP purified as a single TLC spot was resolved into three peaks using HPLC. These peaks were also observed when cells were labelled with [(3)H]phosphatidylglycerol, an exogenous BMP precursor, and with [(33)P]P(i). Electrospray MS of BMP from control cells showed that the first two peaks contained the same molecular species (mainly C(22:6)n-3/C(22:6)n-3 and C(18:1)n-9/C(22:6)n-3) while the third peak mainly contained the C(18:1)n-9/C(18:1)n-9 species. The stereoconfiguration analysis of the compounds revealed an sn-glycero-3-phospho-1'-sn-glycerol configuration for the first peak and sn-glycero-1-phospho-1'-sn-glycerol configurations for the other two. BMP from rat testis was used to establish the positions of the acyl groups. More than 70% of its acyl chains were C(22:5) n-6. It was separated on HPLC into three peaks that co-migrated with the three peaks of BMP from U(III) cells. Lipase activity and NMR analysis of the second peak showed that fatty acids esterified the primary alcohol group on each glycerol moiety. We conclude that the three peaks are stereoisomeric compounds with different acyl-chain locations and may be the result of different metabolic fates depending on subcellular localization.
在大鼠子宫基质细胞（U(III)细胞）中，二十二碳六烯酸（DHA）大量酯化于烯基酰基甘油磷酸乙醇胺和一种未知的磷脂中，该未知磷脂仅占总磷脂的0.7%。使用质谱法将后者鉴定为双（单酰基甘油）磷酸酯（BMP）。使用C(18:3)n-3和C(20:5)n-3进行的掺入研究表明，BMP对掺入DHA和(n-3)系列的C(22)多不饱和脂肪酸具有高度特异性。相比之下，(n-6)系列的多不饱和脂肪酸从未掺入BMP中。将U(III)细胞与5 microM DHA孵育24小时后，BMP中的DHA含量从总酰基链的36%增加到71%。作为单个薄层色谱斑点纯化的[(3)H]DHA标记的BMP使用高效液相色谱法分离为三个峰。当细胞用[(3)H]磷脂酰甘油（一种外源性BMP前体）和[(33)P]P(i)标记时，也观察到了这些峰。对照细胞中BMP的电喷雾质谱显示，前两个峰包含相同的分子种类（主要是C(22:6)n-3/C(22:6)n-3和C(18:1)n-9/C(22:6)n-3），而第三个峰主要包含C(18:1)n-9/C(18:1)n-9种类。对这些化合物的立体构型分析表明，第一个峰为sn-甘油-3-磷酸-1'-sn-甘油构型，另外两个峰为sn-甘油-1-磷酸-1'-sn-甘油构型。使用大鼠睾丸中的BMP来确定酰基的位置。其酰基链中超过70%为C(22:5)n-6。它在高效液相色谱上分离为三个峰，与U(III)细胞中BMP的三个峰共迁移。第二个峰的脂肪酶活性和核磁共振分析表明，脂肪酸酯化了每个甘油部分上的伯醇基团。我们得出结论，这三个峰是具有不同酰基链位置的立体异构体化合物，可能是由于亚细胞定位不同导致不同代谢命运的结果。
