Figure 2.

Synthesis of phospholipid/oxidized phospholipid from 2-arachidonoyl-lysophospholipid or 2-eicosanoid lysophospholipid by sn-1 acyltransferase. A, extracted ion chromatograms of PC/oxidized PC synthesized by murine hepatic microsomal sn-1 acyltransferase activity(ies) utilizing 2-AA-LPC or 2–15-HETE-LPC as substrate. Microsomal homogenates isolated from mouse liver were incubated with the indicated substrates for 5 min at 37 °C in 75 mm sodium phosphate buffer (pH 7.4). After incubation, 14:1-PC was added as an internal standard. The lipids were extracted and analyzed by LC-MS. The extracted ion chromatograms (with a 5-ppm mass window) of the metabolic products 18:0/20:4-PC-d₉ (m/z 819.6565) and 18:0/15-HETE-PC-d₉ (m/z 835.6514) are shown. B, extracted ion chromatograms of oxidized PE synthesized by murine hepatic microsomal sn-1 acyltransferase activity(ies) utilizing 2–15-HETE-LPE as described above. After incubation, 16:1-PE was added as an internal standard. The extracted ion chromatograms (with a 5-ppm mass window) of the metabolic product 18:0/15-HETE-PE (hydroxy ¹⁸O) (m/z 786.5530) is shown. C and D, MS¹ spectrum (C) and MS² spectrum (D) of 18:0/20:4-PC-d₉. E and F, MS¹ spectrum (E) and MS² spectrum (F) of 18:0/15-HETE-PC-d₉. G and H, MS¹ spectrum (G) and MS² spectrum (H) of 18:0/15-HETE-PE (hydroxy ¹⁸O). I–K, specific activities of sn-1 acyltransferase–mediated production of 18:0/20:4-PC-d₉ (I), 18:0/15-HETE-PC-d₉ (J), and 18:0/15-HETE-PE (hydroxy ¹⁸O) (K) from 2-AA-LPC-d₉ (10 μm), 2–15-HETE-LPC-d₉ (10 μm), and 2–15-HETE-LPE (hydroxy ¹⁸O), respectively, in the presence of 18:0-CoA (10 μm). Values are the average of four independent preparations. Error bars represent S.D.