Radiolysis Study of the Alloxan-Dialuric Acid Couple: I. The Reduction of Alloxan by e aq - and ⋅COO - Radicals
1980; Radiation Research Society; Volume: 83; Issue: 2 Linguagem: Inglês
10.2307/3575278
ISSN1938-5404
AutoresChantal Houée‐Levin, M Gardès-Albert, C. Ferradini, J. Pucheault,
Tópico(s)Mass Spectrometry Techniques and Applications
ResumoReduction of alloxan (A) to dialuric acid (AH/sub 2/) by e/sub aq//sup -/ and COO/sup -/ has been studied by ..gamma.. and pulse radiolysis. By ..gamma.. radiolysis, the G-value for dialuric acid formation is equal to G(AH/sub 2/) = 4.7 +- 0.25 eq/100 eV = G/sub H/ + G/sub e//sub aq//sup -/ +G/sub OH/ - 2G/sub H/sub 2/O/, dialuric acid being oxidized by H/sub 2/O/sub 2/. Pulse radiolysis gives evidence for an intermediate AH formation which should be of a semiquinone type, and whose absorption spectrum has been characterized. Its production rate constants by reactions of e/sub aq//sup -/ and COO/sup -/ with alloxan were measured: k(e/sub aq//sup -/ + A) = (1.7 +- 0.02) x 10/sup 10/ M/sup -1/ sec/sup -1/; k(COO/sup -/ + A) = (3.7 +- 1.1) x 10/sup 7/ M/sup -1/ sec/sup -1/. AH disappears by disproportionation with a rate constant 2k = (1.6 +- 0.03) x 10/sup 8/ M/sup -1/ sec/sup -1/.
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