Transferrin and Iron Uptake by Isolated Rat Liver Mitochondria

Abstract

Ulvik, R., Prante, P. H., Koller, M. E. & Romslo, I. Transferrin and Iron Uptake by Isolated Rat Liver Mitochondria. Scand. J. clin. Lab. Invest. 36, 539–546, 1976.

Isolated rat liver mitochondria accumulate iron from the suspending medium when [⁵⁹Fe]transferrin is used as a model compound. The accumulation proceeds by two different mechanisms, i.e. by an energy-independent and an energy-dependent (uncoupler sensitive) mechanism, which have different time, pH, and temperature dependencies. The energy-dependent accumulation, which is inhibited by ruthenium red and sulphydryl reagents, reaches a saturation level of approx. 30 pmoles iron/mg protein during 30 min incubation. The energy-independent accumulation of iron-transferrin reveals no saturation kinetics, it is inhibited neither by ruthenium red nor by N-ethylmaleimide, and it proceeds linearly for at least 90 min. With [¹²⁵I]transferrin as a model compound, quantitatively the energy-independent accumulation is as reported for [⁵⁹Fe]transferrin. There is, however, no energy-dependent accumulation of [¹²⁵I]transferrin. The results indicate that the energy-dependent accumulation of [⁵⁹Fe]transferrin represents a process by which mitochondria accumulate iron from transferrin.

Key Words:

• Iron
• accumulation of
• mitochondria
• transferrin
• dissociation of
• uncoupler