A kinetic study on the distribution of Cu(II)-ions between albumin and transferrin.
Serum albumin (human, bovine) has a specific Cu(II)-ion binding site, and is proposed to act as a copper transport protein in blood plasma. Human transferrin, normally about 30% saturated with iron in vivo, has two sites/molecule capable of complexing Cu(II); one more strongly than the other (Hirose et al. 1996). The present study shows that this binding site has a slightly stronger affinity for Cu(II) than that on the albumins. However, both human- and bovine albumin could take up part of the transferrin bound Cu(II), the second order rate constant for the reaction estimated to 12 mM(-1) min(-1) for both species. In vivo the albumin concentration is considerably higher than that of iron-free transferrin, and it seems unlikely that the latter can compete with albumin for non-ceruloplasmin cupric ions.
Løvstad
Rolf A
RA
Department of Medical Biochemistry, University of Oslo, PO Box 1112 Blindern, 0317 Oslo, Norway.
D000418:Albumins / Q000378:metabolism*; D000818:Animals; D002417:Cattle; D003300:Copper / Q000378:metabolism*; D003627:Data Interpretation, Statistical; D006801:Humans; D007700:Kinetics; D013053:Spectrophotometry; D013997:Time Factors; D014168:Transferrin / Q000378:metabolism*
D000418:Albumins; D014168:Transferrin; D003300:Copper