Fig. 5.

Lipid analysis of Golgi membrane. a Representative liquid chromatography-mass spectrometric chromatograms of the Golgi lipid extract. Shown is the total ion chromatogram and the extracted ion chromatogram (XIC) of phosphatidylcholine (PC) (16:1) with m/z 508.30. Note that multiple peaks were detected in the XIC channel indicating that there are PC isomers with different acyl chain length. Peaks detected at 5.94, 6.99, and 10.12 min for m/z 508.30 are consistent with PC having different acyl chain length combinations of 10:0/6:1, 8:0/8:1, or 10:1/6:0. b Representative precursor and product ion spectra of XIC with m/z 508.30. The precursor ions are assigned with mass error <3 ppm. Characteristic fragment at m/z 184.07 (representing choline phosphate) further confirms the identity of PC