Nucleotide sequence of cDNA for porcine heme oxygenase and its expression in Escherichia coli

The nucleotide sequence of a cDNA for porcine heme oxygenase was determined. The open reading frame encoded a polypeptide of 288 amino acid residues with a molecular mass of 33,074 Da. A prokaryotic expression plasmid carrying porcine heme oxygenase cDNA was constructed and transfected into Escherichia coli cells. The full-length heme oxygenase expressed was localized in the bacterial membranes. Two small-sized heme oxygenases with no membrane-bound properties were also detected, suggesting that in E. coli cells a considerable amount of the enzyme expressed was degraded.