Transferrin and iron uptake by isolated rat liver mitochondria.
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.
D000818:Animals; D004734:Energy Metabolism; D005033:Ethylmaleimide / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D007501:Iron / Q000378:metabolism*; D008930:Mitochondria, Liver / Q000378:metabolism*; D051381:Rats; D012430:Ruthenium Red / Q000494:pharmacology; D013696:Temperature; D013997:Time Factors; D014168:Transferrin / Q000378:metabolism*
D014168:Transferrin; D012430:Ruthenium Red; D007501:Iron; D005033:Ethylmaleimide