Effects of spermine on transferrin and iron uptake by reticulocytes: II. Changes in intravesicular pH.
An increase in extracellular spermine concentration brought about a progressive rise in intralysosomal pH in rabbit reticulocytes. Since intracellular release of iron from transferrin is believed to involve the protonation of the iron-transferrin complex, the rise in intralysomal pH could account for the inhibitory effect of spermine on iron uptake. The inhibition could be reversed if spermine was removed by washing. As a result of spermine treatment, more acid-labile N-terminal monoferric transferrin and less apotransferrin were released from the cell. These results are consistant with the protonation theory of iron release.
D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D007501:Iron / Q000097:blood*; D008247:Lysosomes / Q000187:drug effects / Q000378:metabolism; D011817:Rabbits; D012156:Reticulocytes / Q000187:drug effects* / Q000378:metabolism; D013096:Spermine / Q000494:pharmacology*; D014168:Transferrin / Q000378:metabolism*
D014168:Transferrin; D013096:Spermine; D007501:Iron