DNA damage induced by sulfite autoxidation catalyzed by copper(ii) tetraglycine complexes

Abstract

Copper(II)/(III) tetraglycine complexes were investigated for their ability to catalyze the autoxidation of sulfite resulting in oxidative DNA damage. The focus of this work is on DNA damage by Cu(III) and oxysulfur radicals formed by the oxidation of S(IV) oxides by dissolved oxygen in the presence of Cu(II) tetraglycine complexes. The results suggest that sulfite is rapidly oxidized by oxygen in the presence of Cu(II) complexes producing Cu(III) tetraglycine, which can be monitored spectrophotometrically at 365 nm. A synergistic effect of Cu(II) with a second metal ion (Ni(II), Co(II) or Mn(II) traces) was observed.

Oxidative DNA damage induced by S(IV) in the presence of Cu(II) and Cu(I) complexes

“…19,21 The oxidation of 2´deoxyguanosine to 8-oxodGuo and both single and double-strand breaks in DNA were observed under the same conditions. 19,21 In the present work, the DNA damage induced by S(IV) in the presence of some Cu(II) peptide complexes in air saturated solution was investigated. Cu(II) peptide complexes can be oxidized to Cu(III) species, as demonstrated by Margerum and co-workers.…”

“…The intensity of DNA damage in the presence of the different Cu(II) complexes and for S(IV) (10-300 µmol L Figure 1) and previous work. 12,16,19,21,34 Due to the synergistic effect of Ni(II) on the oxidation of Cu II G 4 in the presence of S(IV) and dissolved oxygen, 12,16,17,21 some experiments were carried out to evaluate the DNA strand breakage as shown in Figure 3. …”

“…[7][8][9][10][11][12][13][14][15][16][17][18] These radicals might cause DNA damage, as already described in our previous work. [19][20][21][22] The literature reports only few studies on DNA damage mediated by Cu(II) (added as a free ion or complex) in the presence of S(IV) and dissolved oxygen. [19][20][21][22][23][24] Previously, we showed that the oxidation of S(IV) in air saturated solution ( 13,14,16,17 In addition, we verified that Cu II G 4 complexes interact with DNA producing strand breaks in significant yields in the presence of S(IV) without or with a second metal ion (traces of Ni(II)).…”

Further studies on the synergistic effect of Ni(II) and Co(II) ions on the sulfite induced autoxidation of Cu(II) penta and hexaglycine complexes

“…[36][37][38][39][40] This redox cycling process of metal ion is of interest in atmospheric process, 3,41,42 treatment of gaseous effluents to assist pollution control systems development [43][44][45] and in the DNA and RNA damage by the sulfur oxy radicals. [46][47][48] The synergistic effect due to the combination of two transition metal ion (in the 2+ oxidation state) in an autocatalytic process, with the initiator being the metal ion at trace level in the 3+ oxidation state, followed by a redox cycling, is fascinating and very complex to be fully understood. Many important aspects must be considered: the oxidation of the second metal ion (initially present or added), how faster is the reoxidation of the reduced metal ion and the stability of the metal ion complexes.…”

Kinetics of the autoxidation of sulfur(iv) co-catalyzed by peroxodisulfate and silver(i) ions

“…[1][2][3][4][5] The role of sulfur(IV) autoxidation in the hydroxylation, epoxidation and oxidative cleavage of DNA, [6][7][8][9][10] in certain metallurgical 11,12 and food technologies, [13][14][15][16] and microbiological processes 17 generates additional motivation to study its mechanistic details. It is now understood that the process does not proceed in the absence of a catalyst in acidic medium.…”