disproportionation

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disproportionation

[‚dis·prə‚pȯr·shə′nā·shən]
(chemistry)
The changing of a substance, usually by simultaneous oxidation and reduction, into two or more dissimilar substances.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
Catalase activity was measured using colorimetric methods based on the dismutation of [H.sub.2][O.sub.2] with CAT.
In DS, Superoxide dismuthase 1 (SOD-1), an antioxidant enzyme encoded on chromosome 21(21q22.1) causes dismutation of superoxide anion into hydrogen peroxide and oxygen resulting in oxidative stress.
In addition to uncoupling, peroxynitrite formation can also occur when levels of nitric oxide are so high that superoxide dismutase is overcome and can no longer provide dismutation activity (Vinten-Johansen, 2000).
Copper is present in a large number of enzymes, which are involved in electron transfer, activation of oxygen, and other small molecules as well as superoxide dismutation [1, 2].
The endogenous antioxidant enzyme includes superoxide dismutase that catalyzes the dismutation of superoxide radicals [23].
The enzyme superoxide dismutase catalyzes the dismutation of superoxide into oxygen and hydrogen peroxide.
Superoxide dismutase activity of all these complexes has been revealed to catalyze the dismutation of superoxide ([O.sub.2.sup.-]), and [IC.sub.50] values were evaluated and discussed.
Superoxide anion can also undergo dismutation to form hydrogen peroxide ([H.sub.2][O.sub.2]), either spontaneously or when catalyzed by the enzyme superoxide dismutase (27).
One unit is defined as the amount of enzyme needed to exhibit 50% dismutation of the superoxide radical.
(12), (19-23) In other words, [Ce.sup.4+] was present in the form of Ce[(OH).sub.2.sup.2+] in the solution, resulting from the oxidization of Ce[(OH).sub.3] in alkaline solution; then the Ce[(OH).sub.3] was converted into Ce[0.sub.2] in a dismutation solid state reaction.
(6) Superoxide dismutase, which catalyses the dismutation of [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] is considered to be the essential enzyme in the defense against the toxic effects of [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII].
Induction of nNOS/iNOS by methamphetamine or MDMA (Figure 3) constitutes part of the mechanism of methamphetamine damage, as selective inhibition or genetic inactivation of nNOS and overexpression of cupper zinc superoxide dismutase (CuZnSOD), an enzyme that catalyzes the dismutation of superoxide into oxygen and hydrogen peroxide, prevent methamphetamine neurotoxicity [23, 37, 38].