Selective inhibition of Fe- versus Cu/Zn-superoxide dismutases by 2,3-dihydroxybenzoic acid derivatives

Abstract

A series of catechol derivatives were synthesised and tested for their ability to inactivate the iron-containing superoxide dismutase (Fe-SOD) from Escherichia coli and the bovine erythrocytes Cu/Zn-SOD. Incubation of catechols with Fe- or Cu/Zn SODs resulted in a time-dependent loss of enzyme activity with highly selective inhibition for the iron-dependent enzyme. Catechol-induced inactivation of SODs was correlated with the auto-oxidation of the catechol compounds to their corresponding ortho-quinone derivatives, which was found to be non-dependent on the presence of enzymes. Mass electrospray experiments on catechol-incubated Fe-SOD provided evidence for the irreversible nature of the inhibition process, yielding to a complex mixture of modified proteins. © 2002 Pharmaceutical Society of Japan.