Solubility of copper and zinc containing proteins before and after 2-mercaptoethanol treatment of liver samples from normal and from chronically copper poisoned sheep.

The distribution between cytosol and pellet of Cu- and Zn-containing proteins was studied in livers from normal sheep and sheep with chronic copper poisoning (CCP). It was found that the relative amount of soluble Cu- and Zn-containing proteins was lower in liver homogenates from CCP sheep than in homogenates from normal sheep. Treatment of homogenate from the livers of 2-mercaptoethanol (ME) increased the solubility of Cu- and Zn-containing proteins, especially in CCP sheep. Oxidation of the liver homogenates from normal sheep with air oxygen gave a decrease in the relative amount of soluble CU-containing proteins and an increase in Zn-containing proteins present in the cytosol. It is proposed that oxidation in vivo of Cu and/or the metal-binding protein causes the observed decrease in soluble CU- and Zn-containing proteins seen in CCP sheep.