HgCl2 increases the methemoglobin prooxidant activity. Possible mechanism of Hg2+-induced lipid peroxidation in erythrocytes

In an attempt to elucidate the mechanism of initiation of peroxidation in HgCl2-treated erythrocytes, the effect of HgCl2 on methemoglobin-catalyzed lipid peroxidation was studied. It was found that HgCl2 reinforces the prooxidant action of methemoglobin. This effect seems not to be due to dissociation or degradation of the hemoglobin molecule to heme-containing fragments or iron-containing products of low molecular weight. The results obtained indicate that Hg2+ increases the binding of oxy- and methemoglobin to liposomes. A suggestion is made that the acceleration of methemoglobin-catalyzed peroxidation by HgCl2 is mainly due to increased binding of methemoglobin to liposomes. On the basis of these results and the results obtained previously the possible mechanism of initiation of peroxidation in Hg2+-treated erythrocytes is discussed.