US EPA

1290173 

Journal Article 

Mechanisms of formation and decomposition of hypervalent chromium metabolites in the glutathione-chromium (VI) reaction 

Moghaddas, S; Gelerinter, E; Bose, RN 

1995 

Yes 

Journal of Inorganic Biochemistry
ISSN: 0162-0134
EISSN: 1873-3344 

57 

2 

135-146 

English 

7861127 

10.1016/0162-0134(94)00019-7 

A long-lived chromium(IV) intermediate is generated during the reaction between Cr(VI) and glutathione in glycine below pH 3. The intermediate reacts with the tripeptide to produce Cr(III) and oxidized glutathione. A dynamic magnetic susceptibility measurement based on a nuclear magnetic resonance method yielded a 2.8 microB magnetic movement for the chromium(IV) species. The intermediate is formed by parallel third-order and second-order processes. The third-order process (k = 5.9 x 10(2) M-2 s-1) involves first-order participation by each of the oxidant, reductant, and hydrogen ions. A hydrogen ion independent pathway leads to a sluggish second-order process (k = 0.11 M-1 s-1) that is first order with respect to reduced glutathione [GSH] and [Cr(VI)]. Chromium(IV) species is reduced to Cr(III) by a second-order process (k = 0.13 M-1 s-1) that is first order in each of [Cr(IV)] and [GSH] and does not depend on [H+]. At pH 3.4, a chromium(V) species was detected as a minor intermediate as well. In the pH range 6.5-7.5, three dominant chromium(V) intermediates were detected. The existence of Cr(IV) in low pH offers an opportunity to examine the mechanism of DNA damage by this rare oxidation state.