Copper-induced oxidative cleavage of glutathione transferase F1-1 from Zea mays.

摘要: Study of the interaction glutathione transferase F1-1 from Zea mays (ZmGSTF1-1) with Cu(II), in presence ascorbate showed that enzyme was rapidly inactivated. The inactivation time and Cu(II) concentration dependent. rate non-linear dependence on concentration, indicating a reversible complex (KD 84.5 ± 6.5 μM) formed. inhibitors S-nitrobenzyl-glutathione or S-methyl-glutathione competes suggesting specificity chemical modification reaction. SDS-PAGE analysis inactivated is fragmented two new bands 13 11 kDa are This shows ZmGSTF1-1 specifically cleaved at single site, by locally generated free radicals, through Fenton-type Sequencing fragments allowed identification binding site ZmGSTF1-1. three-dimensional structure reveals localized within glutathione-binding (G-site) His40 Gln53 most likely residues provide coordination sites for binding. These findings were confirmed site-directed mutagenesis. copper-induced oxidative cleavage reaction may function as detoxification route protecting plant cells deleterious effects.