Competitive inhibition of Cu, Zn superoxide dismutase by monovalent anions

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Abstract

Polarographic measurements showed that N3 and halides in hibit the activity of bovine Cu, Zn superoxide dismutase in a competitive fashion, as previously demonstrated for CN and OH. All anions increase the spin-lattice nuclear magnetic relaxation time (T1) of aqueous solutions of the enzyme as well, but the stability constants measured from T1 data are lower than those calculated from activity data. The results suggest that substrate and anionic inhibitors bind during the catalytic action at the water coordination position of the enzyme copper, and that these inhibitors may have a greater affinity for the cuprous form of the enzyme which is generated in the catalytic cycle.

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    Citation Excerpt :

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