Lipoxygenases: structural principles and spectroscopy.

Lipoxygenases catalyze the formation of fatty acid hydroperoxides, products used in further biochemical reactions leading to normal and pathological cell functions. X-ray structure analysis and spectroscopy have been applied to elucidate the mechanism of lipoxygenases. Two X-ray structures of soybean lipoxygenase-1 reveal the side chains of three histidines and the COO- of the carboxy terminus as ligands to the catalytically important iron atom. The enzyme contains a novel three-turn pi-helix near the iron center. Spectroscopic studies, including electron magnetic resonance, X-ray absorption spectroscopy, infrared circular dichroism, and magnetic circular dichroism, have been applied to compare lipoxygenases from varied sources and with different substrate positional specificity.