Pseudomonas syringae ethylene-forming enzyme reveal a branched mechanism. In one branch, an apparently typical 2-oxoglutarate oxygenase reaction to give succinate, carbon dioxide, and sometimes pyrroline-5-carboxylate occurs, reaction of
EC 1.13.11.34. Alternatively, Grob-type oxidative fragmentation of a 2-oxoglutarate-derived intermediate occurs to give ethylene and carbon dioxide,
EC 1.13.12.19. Fragmentation to give ethylene is promoted by binding of L-arginine in a nonoxidized conformation and of 2-oxoglutarate in an unprecedented high-energy conformation that favors ethylene, relative to succinate formation. Induced fit reaction mechanism, detailed overview
