Mechanism of ferritin iron uptake: activity of the H-chain and deletion mapping of the ferro-oxidase site. A study of iron uptake and ferro-oxidase activity of human liver, recombinant H-chain ferritins, and of two H-chain deletion mutants.

摘要: To study the functional differences between human ferritin H- and L-chains role of protein shell in formation growth iron core, we have compared kinetics oxidation uptake purified from liver (90% L) H-chain homopolymer overproduced Escherichia coli (100% H). As a control for autocatalytic activity, analyzed effect Fe(III) on reaction. The results show that has faster rates than all conditions difference is reduced which autocatalysis high: i.e. at pH 7 presence core. We also properties two engineered H-chains, one lacking last 22 amino acids carboxyl terminus other missing first 13 residues terminus. These mutant proteins assemble ferritin-like maintain ability to catalyze oxidation. deletion terminus, however, prevents stable It concluded an site separated sites transfer hydrolysis either integrity molecule or acid sequences forming hydrophobic channel necessary core formation.