Transferrin, a mechanism for iron release.

摘要: Iron release from transferrin has been investigated in mildly acidic and media the presence of formate, acetate citrate. It occurs first N-terminal iron-binding site (N-site) holoprotein. is independent nature concentration competing ligands controlled by a slow proton transfer; second-order rate constant k1 = (7.4 +/- 0.5) x 10(4) M-1 s-1 which can be attributed to rate-limiting gain protein ligand subsequent fast decarbonation N-site. loss C-terminal (C-site) slower than that N-site two pathways. The favoured below pH 4 does not involve formation an intermediate ternary complex. proton-triggered binding site; k3 (2.25 0.05) s-1. second pathway above involves mixed protein-ligand iron takes place through protonation complex depends on ligand. faster citrate acetate; k4 (1.75 0.10) 10(3) for (85 5) acetate. All these phenomena possibly describe changes conformation sites.