Oxygen transporting ability of synthetic hemes embedded in liposomes

The authors derived the oxygen-binding site of hemoglobin (heme) to amphiphilic heme compounds and succeeded in reversible oxygen-binding under physiological conditions by embedding the synthetic heme derivatives in a phospholipid liposome. Viewing stereostructure and lipophilic and/or amphiphilic property of heme to enhance both its oxygen-binding ability and its compatibility with a phospholipid bilayer, the authors synthesized three different heme derivatives efficiently embedded in a bilayer (not in an aqueous inside region of liposome) of the phospholipid. It was found that oxygen binding by hemes embedded in liposome proceeds in the same way as binding by hemoglobin, but their oxygen-binding affinity is slightly weaker than that of red blood cells.