Recombinant human erythrocyte cytochrome b5

Mutations in the expression vector which encodes the lipase-solubilized bovine liver microsomal cytochrome b5 facilitate the development of a recombinant human erythrocyte cytochrome b5 and its expression in Escherichia coli, for defining its functional and physical features. The human cytochrome b5 protein consists of two extra His residues than the bovine cytochrome b5 protein. The midpoint reduction potential of the human recombinant form is -9 plus or minus 2 mv and depends on the value of pH. One-dimensional H NMR spectroscopy of the ferricytochrome form of the erythrocyte reveals the occurrence of 90% of major orientation and 10% of minor orientation binding between the protein and heme.