The effects of plumbous ion on protein biosynthesis in reticulocytes.

Plumbous ion a potent inhibitor of hemoglobin synthesis by reticulocytes in vivo, is not as effective in inhibiting in vitro globin synthesizing systems prepared from these cells. The reticulocyte is considerably more sensitive to Pb2+ than are leukemic leukocytes, HeLa cells or bacteria. In fact, protein synthesis in leukemic leukocytes is actually stimulated by Pb2+. The synthesis of non-heme protein as well as hemoglobin is inhibited by Pb2+ in reticulocytes and the synthesis of alpha chains is inhibited to a greater degree tcids into reticulocytes. All of these observations are consistent with the biosynthesis of heme rather than any of the steps in protein biosynthesis being the locus for inhibition of hemoglobin synthesis by low levels of plumbous ion. Also, there is marked biological variations in the susceptibilities of reticulocytes from different rabbits to Pb2+.