Figure 3.

Proposed pathway for the 2C-shortening of fatty acids by UPOs (and their H₂O₂ cosubstrate) showing the structures of oleic acid (1), its monohydroxylated derivatives at ω-1 (2) and ω-2 (3) positions, the mono-keto derivatives at ω-1 (4) and ω-2 (5) positions, the dioxygenated hydroxy-keto (6) and keto-hydroxy (7) derivatives, the di-keto (8), in equilibrium with its keto-enol isomer (9) derivatives, and finally the 2C shortened dicarboxylic acid (10) from H₂O₂ cleavage of the diketo C-C bond.