In:
FEBS Letters, Wiley, Vol. 158, No. 1 ( 1983-07-11), p. 143-146
Abstract:
To gain an understanding of the mechanism by which the hydroxyl free radical can arise in superoxide generating systems and learn how different chelaters of iron can inhibit this reaction, a pulse radiolysis kinetic study of the reaction of O − 2 with Fe(III)EDTA, Fe(III)HEDTA and Fe(III)DETAPAC (or DTPA) was undertaken. Superoxide reacts readily with Fe(III)EDTA and Fe(III)HEDTA with a pH‐dependent second‐order rate constant having values of 1.9 × 10 6 M −1 .s −1 and 7.6 × 10 5 M −1 .s −1 at pH 7, respectively. However, the rate constant for the reaction of O − 2 with Fe(III)DETAPAC was found to be much slower, the upper limit for the rate constant being 10 4 M −1 .s −1 . These results in conjunction with spin‐trapping experiments with Fe(II)EDTA, Fe(II)HEDTA, Fe(II)DETAPAC and H 2 O 2 suggests that DETAPAC inhibits the formation of OH by slowing the reduction of Fe(III) to Fe(II) and not by inhibiting the Fenton reaction.
Type of Medium:
Online Resource
ISSN:
0014-5793
,
1873-3468
DOI:
10.1016/0014-5793(83)80695-4
Language:
English
Publisher:
Wiley
Publication Date:
1983
detail.hit.zdb_id:
1460391-3
SSG:
12
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