Possible Interaction: Ascorbate and Cupric Cation

“The apoptosis-inducing activity of ascorbate is stimulated by Cu2+ , lignin and ion chelator, and inhibited by catalase, Fe3+, Co2+ and saliva.”

“ Ascorbate and cysteine, which will reduce Cu2+ but have little or no affinity for Cu+, also stimulated GSNO decomposition in the presence of Cu2+ , but did not inhibit it at higher concentrations.”

“Copper Cu2+ ), when added with the ascorbate solution at 5 micrograms/ml (0.022 mM), exhibited a catalytic effect on the inactivation of these viruses.”

“ Ascorbate plays a dual role: it reduces the cupric complex to the corresponding cuprous state and serves as a source for H2O2, which, in turn, reacts with the reduced copper complex, in a Fenton reaction.”

“Similarly, intracellular ascorbate concentrations of 1–2 mM also prevented Cu2+ -induced lipid peroxidation in LDL and cells.”

“The inclusion of Cu2+ (0.5-2.0 microM) remarkably enhanced the ascorbate (0.5 mM)-induced inactivation of purified PON1.”

“In contrast to a limited inactivation by Fe2+ (2.0 μM), the inclusion of Cu2+ (0.1–1.0 μM) remarkably enhanced the inactivation of PON1 in the presence of ascorbate (0.5 mM).”

“On the other hand, ascorbate is readily oxidized in the presence of transition metal ions, (especially cupric ion ) and accelerates lipid peroxidation in tissue homogenates by producing free radicals.”

“ Ascorbate and either soluble complexes of Cu(II) or Fe(III) provoked changes in red cell morphology, alteration in the polypeptide pattern of membrane proteins, and significant increases in methemoglobin.”

“Since trace levels of transition metal ions including, Cu2+ and Fe3+, promote oxidation of ascorbate , we examined the effects of the chelating agents, cuprizone and deferoxamine, and of CuSO4 and FeCl3 on ascorbate-induced constriction and blockade of EDHF in the perfused rat mesentery.”