[Purification and functional identification of the recombinant human CREG/myc-His glycoprotein].

OBJECTIVE:To purify the recombinant human cellular repressor of EIA stimulated gene (hCREG)/myc-His glycoprotein and confirm the biological function of hCREG/myc-His which could inhibit the proliferation of human internal thoracic artery smooth muscle cells (HITASY) cultured in vitro. METHODS:The recombinant hCREG/myc-His protein was purified with Ni-NTA column according to 6 x His affinity chromatographic theory. The recombinant hCREG/myc-His protein was desalted by HiTrap Desalting Column. The effect of recombinant hCREG/myc-His glycoprotein of different concentration (0.5 microg/ml, 1 microg/ml and 2 microg/ml) on proliferation of HITASY cells was studied by flow cytometric analysis and the effect of recombinant protein on proliferation of HITASY cells was confirmed by BrdU incorporation method. RESULTS:The recombinant hCREG protein was purified with Ni-NTA column according to 6 x His affinity chromatographic theory. The concentration of recombinant hCREG protein which has been concentrated and desalted was determined to be 1.6 mg/ml and the purity of recombinant protein reached 92%. The protein was identified to be glycosylated. The recombinant hCREG protein was identified to inhibit the proliferation of HITASY cells cultured in vitro and the inhibition effect was stronger in low-dosage group than that in high-dosage group by flow cytometric analysis. The proliferation of HITASY cells cultured in vitro with 2 microg/ml recombinant hCREG protein was inhibited significantly compared with that in control group according to the BrdU incorporation result. There was statistical difference among the groups (P < 0.05). CONCLUSION:The purification of recombinant hCREG/myc-His glycoprotein with biological activity provides an experiment platform for function study and engineering production of hCREG protein.