Lipoxygenases are iron-containing dioxygenases the catalyze the hydopeoxidation of polyunsaturated lipids. This laboratory has obtained the first primary sequence of lipoxygenase, the L-1 isozyme of soybean. It contains a 40 amino acid sequence region which might contain the Fe- octahedral binding site whose presence in the protein is supported by physical evidene. The sequence is highly conserved in the other two major isozymes of soybeans. He now proposes to clone and express the enzyme in E.coli in high amounts, to determine its three dimensional structure by x-ray crystallography and to perform site-directed mutagenesis of selected possibly key amino-acids in the enzyme's sequence. This research will contribute to the ultimate understanding of structure function relationship of the lipoxygenases and to a better preception of the role of the various ligands in non-heme non-sulfur iron proteins. These are expecially interesting enzymes because while catalyzing the same primary reaction, they exhibit a great diversity in their enzymic behavior. Thus a wide range of behavior remains to be explained by rather limited variations in structure. Dr. Axelrod has had a long and distringuished career in enzymology and has been responsible for much of our fundamental knowledge about plant lipoxygenases.
