Effect of Zinc on Cytochrome Oxidase Activity

Abstract

Summary

1. Excess dietary zinc resulted in lowered growth, hemoglobin concentration and cytochrome oxidase activity in the rat. 2. The addition of copper to the zinc diet increased growth and hemoglobin, but to sub-optimum levels, whereas the cytochrome oxidase activity was raised to a greater than normal level. 3. A highly significant correlation was found between hemoglobin level and cytochrome oxidase activity. 4. The inhibitory effect of zinc was not due to the presence in the homogenate of free zinc ions, since the in vitro addition of inorganic zinc to normal rat hearts in amounts equivalent to that found in the zinc-toxic hearts had no effect on the activity of cytochrome oxidase.