title: Electrolysis-mediated irreversible inactivation of lipoxygenase directed toward electroaffinity labelling.
abstract: Irreversible inhibition of soybean lipoxygenase-1 (SL-1) was accomplished via a controlled potential oxidative electrolysis of 1,5-dihydroxynaphthalene (1,5-DHN) at +0.8 V vs SCE. The inactivation of SL-1 with this known inhibitor was greatly enhanced under these electrolytic conditions to which the enzyme itself was stable. Electrolyses were run at 0 degree C in a 0.05 M phosphate buffer, pH 7.0, using graphite cloth electrodes. The rate of inactivation was observed to be limited by and dependent on the anodic oxidation of 1,5-DHN. The non-oxidizable (at this potential) inhibitor indomethacin was shown to protect the enzyme from irreversible inactivation, however, an external nucleophile (2-mercaptoethanol) had little effect. These initial studies support the capability of such electrochemical methods for the site-specific covalent modification (affinity labelling) of lipoxygenase, and perhaps other enzymes.
mesh_terms: D004563:Electrochemistry; D007700:Kinetics; D016859:Lipoxygenase Inhibitors; D009284:Naphthols / Q000494:pharmacology*; D010084:Oxidation-Reduction; D010944:Plants / Q000201:enzymology*; D013025:Glycine max; D013056:Spectrophotometry, Ultraviolet
chemical_list: D016859:Lipoxygenase Inhibitors; D009284:Naphthols; C028289:1,5-dihydroxynaphthalene