Superoxide and peroxynitrite inactivate aconitases, but nitric oxide does not.
The Escherichia coli and recombinant human cytosolic aconitases are inactivated by O2-., with a rate constant of approximately 3 x 10(7) M-1 s-1; the corresponding value for the porcine mitochondrial aconitase is approximately 0.8 x 10(7) M-1 s-1. Nitric oxide, which is reported to inactivate aconitase, did not do so at a perceptible rate, while incubation with peroxynitrite led to a rapid loss of aconitase activity. We propose that the reported inactivation of aconitase by nitric oxide in vivo is actually mediated through peroxynitrite, the product of the reaction between O2-. and NO..
Department of Biochemistry, Duke University Medical Center, Durham, North Carolina 27710.
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Hausladen
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Fridovich
D000154:Aconitate Hydratase / Q000037:antagonists & inhibitors*; D000818:Animals; D004926:Escherichia coli / Q000201:enzymology; D006801:Humans; D009566:Nitrates / Q000494:pharmacology*; D009569:Nitric Oxide / Q000494:pharmacology*; D013481:Superoxides / Q000494:pharmacology*; D013552:Swine
D009566:Nitrates; D013481:Superoxides; C039642:peroxynitric acid; D009569:Nitric Oxide; D000154:Aconitate Hydratase