MOLECULAR STRUCTURE OF N-ACETYL CYSTEINE METAL COMPLEXES

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This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. N-acetyl-L-cysteine (NAC), a natural antioxidant, improves the efficiency of chelating agents used against heavy metal poisoning and facilitates the excretion of Cr(III), Cd(II) and Pb(II), but not of Hg(II). Recent bio-tests on NAC complexes with transition biometals (Zn2+, Co2+, Co3+, Fe2+) showed significant anti-inflammatory activity. The goal of our proposed research is to study the structure of NAC complexes with heavy metals, and transition biometals, in solid state and in aqueous solution at physiological pH and pH = 8.5, using different [NAC]/[Mn+] ratios and [Mn+] = 10 and 100 mM. In this study, we will combine the results from different spectroscopic techniques, such as extended x-ray-absorption fine structure (EXAFS), multi-nuclear NMR, Raman and IR, to identify the local structure around the central metal ion in these complexes. We will use the method that we have developed for EXAFS data analysis of mixtures for similar Cd(II), Hg(II) and Pb(II) complexes with cysteine and penicillamine (3,3'-dimethyl cysteine), including Principal Component Analysis (PCA) of the EXAFS spectra. The aim of the current study is to provide a basis for better understanding of the detoxification treatments and the anti-inflammatory activities with the use of cysteine derivatives as complex-forming agents.