Protein Engineering: Modified Hemoglobin as a Blood Substitute

Does the race for an efficient and safe blood substitute have a front‐runner? Since hemoglobin plays a crucial role in the transport of oxygen in the human body, most of the research into blood substitutes concentrates on this protein. However, because even hemoglobin in one's own body can induce extreme immune reactions, its administration is not without danger. Nagai et al. have now succeeded in modifying this protein by genetic engineering, and several of the problems so far encountered—decomposition of hemoglobin into dimers, prohibitively high oxygen affinity—have been solved. The experiments on rats and dogs with regard to the suitability of solutions of this modified hemoglobin as a blood substitute have been successful.