Transferrin synthesized in cultured human fibroblasts is associated with tubulins and has iron binding capacity

In a previous report (13), using immunocytochemical and fluorescence-labeli ng techniques, we demonstrated that transferrin is synthesized in cultured human fibroblasts and that it is associated with tubulins in the cells. The se morphological findings led us to attempt to elaborate those issues in mo re detail by biochemical methods. In this report, we mere able to prove the association of transferrin produced in cells with tubulins. In addition, t he transferrin associated with tubulins was found to bind to iron. These re sults suggest that endogenous transferrin plays a role in preventing damage caused by free radicals which can be induced by the interaction of iron wi th the hydrogen peroxide produced in cells.