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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.

Megasphaera elsdenii reveals a short-chain acyl-CoA dehydrogenase (SCAD), which exhibits a molecular mechanism. The functioning is controlled by cloning and ordering the gene coding for SCAD. The suggested functioning needs an amino acid residue that is recognized by site-directed mutagenesis. Identification of the amino acid order of the 50 N-terminal residues of SCAD is required to clone the gene. Two groups of varying oligonucleotide primers are prepared by the order of the data, and a 120-bp specific probe from Megasphaera elsdenii DNA is produced by a polymerase chain reaction process.

Researchers assembled the coding sequence for human serum transferrin from restriction fragments developed from a complete cDNA clone isolated from a human liver cDNA library. The assembled clone was introduced into the expression vector pNUT and stably transfected into altered baby hamster kidney (BHK) cells, resulting in secretion of around 125 mg/L recombinant protein into the tissue culture medium.