CONFORMATIONAL-CHANGES OF LIPOXYGENASE (LOX) IN MODIFIED ENVIRONMENTS- CONTRIBUTION TO THE VARIATION IN SPECIFICITY OF SOYBEAN LOX TYPE-1

The addition of water-soluble cosolvents in the reaction medium of typ e 1 soybean lipoxygenase can modify the selectivity of the enzyme in t he hydroperoxide synthesis reaction. This also results in changes in s econdary reactions such as carbonyl compound formation. The possibilit y of a conformational change of the enzyme due to variations in its mi croenvironment was considered. Using enzyme immobilization and laser v isible Raman spectroscopy, both indirect and direct observations of su ch a protein conformational rearrangement are described. Subtle modifi cations in the secondary and/or tertiary structures, for example in mi croenvironments of Tyr and Trp residues, in orientations of lateral si de chains were evidenced, and their importance to enzyme specificity i s discussed.