FIGURE 3.

Transformation of 9R-HPODE by recombinant AOS (ATEG_02036). A, NP-HPLC-MS/MS analysis of metabolites. B, MS³ spectrum (m/z 311 → 293 → full scan) of the α-ketol, 9-hydroxy-10-oxo-(12Z)-octadecenoic acid. The intense ions at m/z 265, 185, 155, and 153 corresponded to m/z 282, 195, 165, and 162 in the MS³ spectrum of 9-hydroxy-10-oxo-(12Z)-[¹³C₁₈]octadecenoic acid. The signal at m/z 155 could be due to the fragment ion ⁻OOC-C₈H₁₅ (possibly due to dehydration at C-9 and cleavage between C-9 and C-10), and the signal at m/z 153 (155–2; loss of H₂) could be due to ⁻OOC-C₈H₁₃ (inset). TIC, total ion current; A⁻, the carboxylate anion; γ-Ketol, 10-oxy-13-hydroxy-(11E)-octadecenoic acid.