Expression, Purification, And Characterization Of Recombinant Homo Sapiens Heme Oxygenase-2 (HMOX2)

In order to characterize human heme oxygenase-2, we overexpressed biosynthetic Homo sapiens heme oxygenase-2 (HMOX2) from Escherichia coli in the T7 expression system as a poly-His tagged fusion construct. The expressed recombinant His10-HMOX2 (35.4 kDa) was first purified by Ni-NTA affinity chromatography, then purified by anion exchange chromatography. The His10-HMOX2’s typical yield was 92 mg from 1 liter of culture medium with purity above 90%. The recombinant HMOX2 was assayed for oxygenase activity, showing oxygenase activity of 69.51 U/mg. The oxygenase activity assay also showed that the purified recombinant HMOX2 tolerated broad ranges of pH (pH 6-9) and temperature (20-95℃). The optimum temperature and pH is 40℃ and pH 8. The HMOX2’s H152A & K89E mutants showed almost no oxygenase activity, which may be the reason of pulmonary haemosiderosis and sensitive to hyperoxia induced tissue injury. Our research may facilitate further studies of HMOX2 structure and function, including the determination of its crystal structure by X-ray diffraction.