The distribution of iron between the metal-binding sites of transferrin human serum.
The Makey & Seal [(1976) Biochim. Biophys. Acta 453, 250--256] method of polyacrylamide-gel electrophoresis in buffer containing 6 M-urea was used to determine the distribution of iron between the N-terminal and C-terminal iron-binding sites of transferrin in human serum. In fresh serum the two sites are unequally occupied; there is preferential occupation of the N-terminal site. On incubation of the serum at 37 degrees C the preference of iron for the N-terminal site becomes more marked. On storage of serum at -15 degrees C the iron distribution changes so that there is a marked preference for the C-terminal site. Dialysis of serum against buffer at pH 7.4 also causes iron to be bound much more strongly by the C-terminal than by the N-terminal site. The original preference for the N-terminal site can be resroted to the dialysed serum by addition of the diffusible fraction.
D001665:Binding Sites; D002951:Citrates; D003956:Dialysis; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D007501:Iron / Q000097:blood*; D013696:Temperature; D014168:Transferrin / Q000378:metabolism*
D002951:Citrates; D014168:Transferrin; D007501:Iron