Spectroscopic characterization of genotoxic chromium(V) peptide complexes: Oxidation of Chromium(III) triglycine, tetraglycine and pentaglycine complexes.

摘要: Evidence is growing that metabolites of Cr(III) dietary supplements are partially oxidized to carcinogenic Cr(VI) and Cr(V) in vivo. Hence, we examined oxidations peptide (triglycine, tetraglycine pentaglycine) complexes by PbO2 at 37°C physiological pH values between 3.85 7.4. The products were characterized EPR UV/Vis spectroscopies electrospray mass spectrometry. At pH3.85, the monomeric produced relatively unstable degraded over min hr under acidic conditions. triglycine had five-line 14N-superhyperfine-coupled signals; giso, (AN) 1.9824 (2.44×10-4cm-1) 1.9825 (2.43×10-4cm-1), respectively. pentaglycine complex a seven-line signal: giso=1.9844; AN=2.27×10-4cm-1. In phosphate buffer (pH7.4 5.85), several intermediates produced, but was end product. For triglycine, complexes, giso (AN, 10-4cm-1) 1.9831 (2.17), 1.9843 (2.27) 1.9844 (2.30), A second signal with unresolved superhyperfine structure observed giso~1.966. 1min, another giso~1.978, which decayed relative other signals time. This chemistry has relevance to: (i) certain types DNA damage Cr carcinogens; (ii) intracellular oxidation Cr(VI); (iii) redox recycling formed from both reduction supplements.