ESR studies of the interaction of copper(II)GHK, histidine, and Ehrlich cells.

The tridentate complex CuGHK does not form ESR detectable adducts upon addition to either glutathione or Ehrlich ascites cells under our conditions. The absence of adducts is consistent with the poor uptake of CuGHK by cells. ESR spectra are used to characterize adduct formation between CuGHK and histidine. The CuGHK-histidine adduct is not stable in the presence of Ehrlich ascites tumor cells. It is argued that a Cu(His)2 complex is formed as a consequence of the interaction of GHK with cells.