Identification of putative residues involved in the accessibility of the substrate-binding site of lipoxygenase by site-directed mutagenesis studies

► Olive LOX1 active site entrance seems cluttered by highly conserved Phe277 and Tyr280. ► Substitution of these residues by less bulky ones improves catalytic efficiency. ► Regio- and stereospecificity of the enzyme are not affected by these substitutions. ► Substrate penetration requires side chain movements of Tyr280 of α2 helix and Phe277. ► These residues might be involved in accessibility of active site in plant LOXs.