1H,13C-NMR and X-ray absorption studies of copper(I) glutathione complexes.
A. Corazza, I. Harvey, P. Sadler
Mar 1, 1996
Citations
113
Citations
Quality indicators
Journal
European journal of biochemistry
Full text
Semantic Scholar
Key Takeaway Key Takeaway: Copper(I)-glutathione complexes show high thermodynamic stability and kinetic lability, potentially providing efficient and specific pathways for copper transport in cells.
Abstract
The tripeptide glutathione (gamma-L-Glu-L-Cys-Gly, GSH) is an important intracellular reducing agent for Cu(II) and complexation agent for Cu(I). We have studied the complexation of Cu(I) to GSH in aqueous solution at a range of pH values and Cu(I):GSH molar ratios by 1H-NMR and 13C-NMR spectroscopy and X-ray absorption spectroscopy. The NMR data are consistent with formation of a complex with approximate 1:1 stoichiometry [Cu(SG)] as the major species with only thiolate sulfur of GSH binding to Cu(I). The rate of exchange of GSH with GS-Cu was determined to 13 s(-1) at 283 K, pH 6.8. X-ray absorption spectroscopic measurements showed that Cu(I) is coordinated to 3.1+/-0.3 sulfur atoms at approximately 0.222 nm in solutions (and solids) containing GSH:Cu in 1:1 and 2:1 mol ratios. The possible structures of polymeric Cu(I)-glutathione complexes are discussed. The high thermodynamic stability of Cu(I)-S bonds in Cu(I)-glutathione complexes coupled with their kinetic lability may provide efficient and specific pathways for the transport of copper in cells.