Lipoxygenase is a distinctive non-heme iron dioxygenase. It was first observed in the seeds of leguminous plants because of its relative abundance there and its ability to carry out certain easily observed catalytic transformations. In spite of this, a physiological role for the enzyme from these sources has been difficult to pinpoint. Evidence that lipoxygenases are involved in two stages of plant growth and development, germination and senescence, has been recently presented and the discovery of mammalian lipoxygenases has led in recent years to a renaissance in investigations of the enzyme. Dr. Funk is trying to characterize a component structure of the enzyme that is critically related to its proposed mechanism of action. While non-heme iron is believed to play a key role in the expression of catalytic activity of lipoxygenase, very little is known about the binding site for the atom in the protein. The structure of the iron site will be studied by Mossbauer spectroscopy, a uniquely selective probe of the electronic environment of metals in proteins. The iron site will also be investigated by X-ray absorption spectroscopy in order to provide confirmation of the structural features revealed by other techniques.
