Lipoxygenases are non-heme iron dioxygenases that catalyze the oxygenation of polyunsaturated fatty acids. Using soybean lipoxygenase-1 as a model, we have shown that two classes of lipoxygenase inhibitors currently in development as potential antiinflammatory agents obtain a significant amount of their potency by reducing the lipoxygenase active-site iron from the active ferric state to the in...