Genetic engineering often means insertion of a gene and
harvest of the protein from huge numbers of bacterial cells.
<span>Hemoglobin, are only functional as an assembly of multiple
sub-units. The ability to efficiently harvest the protein of interest and purify
it away from all the other proteins normally produced by the host cell, is one
of the major limiting factors for the large scale production of genetically
engineered hemoglobin.</span>
