Fig. 5.

TbPLA₁ functions to synthesize long-chain unsaturated lysoGPCho intermediates.

A. Positive ion ESI-MS-MS spectrum of m/z 184 lipid precursors in total lipid extracts from T. brucei WT cells. Identities of the major [M+H]⁺ ions are indicated as well as internal standard lysoGPCho [M+H]⁺ peaks.

B. Positive ion ESI-MS-MS short-range spectra of the parents of the m/z 184 ion from total lipid extracts from WT and TbPLA₁ mutant cell lines. The major sets of lysoGPCho [M+H]⁺ metabolites detected are boxed and annotated next to the m/z peak from which they are derived. The numbers in place of x:y refer to the total number of sn-2 FA carbon atoms (x) and their degree of unsaturation (y). Panel insets are similar short-range spectra from lipid extracts spiked with lysoGPCho internal standards used for quantitative purposes (Table 2).