Fig. 1

Expression and purification of SFRP5 protein. a Identification of pET30-SFRP5 expression. M marker (97.4kd,66.2kd,43.1kd,31.2kd,21.2kd,14.4kd). 1. Precipitate of ultrasound-disrupted E. coli cells induced by pET30-SFRP5 for 4 h; 2. Supernatant of ultrasound-disrupted E. coli cells induced by pET30-SFRP5 for 4 h; 3. Ultrasound-disrupted E. coli cells induced by pET30-SFRP5 for 4 h; 4. Ultrasound-disrupted E. coli cells. b The supernatant of the disrupted bacteria was subjected to hydrophobic chromatography, and the bacterial supernatant protein was added to 2 M ammonium sulfate, followed by elution. M marker (97.4kd,66.2kd,43.1kd,31.2kd,21.2kd,14.4kd). 1-9: elusion products. c The hydrophobic chromatography eluate was titrated to PH 8.0 and subjected to ion exchange chromatography. 1. DEAE sample before loading; 2. DEAE penetration sample; 3. 20 mM PB 50 mM NaCl PH 8.0 eluent 1; M:Marker (130kd,100kd,70kd,55kd,35kd,25kd,15kd,10kd); 4: 20 mM PB 50 mM NaCl PH 8.0 eluent 2; 5: 20 mM PB 50 mM NaCl PH 8.0 eluent 3; 6: 20 mM PB 50 mM NaCl PH 8.0 eluent 4; 7: 20 mM PB 100 mM NaCl PH 8.0 eluent 1; 8: 20 mM PB 100 mM NaCl PH 8.0 eluent 2; 9: 20 mM PB 100 mM NaCl PH 8.0 eluent 3. d Affinity chromatography: 20 mM PB 50 mM NaCl 8.0 pH 8.0 ion exchange chromatography eluate was subjected to nickel column affinity chromatography. 1. Ni sample before loading; 2. Ni penetration sample; 3. 20 mM PB 0.15 M NaCl 5 mM imidazole PH 8.0 eluent 1; M Marker (130kd,100kd,70kd,55kd,35kd,25kd,15kd,10kd); 4. 20 mM PB 0.15 M NaCl 5 mM imidazole PH 8.0 eluent 2; 5. 20 mM PB 0.15 M NaCl 5 mM imidazole PH 8.0 eluent 3; 6. 20 mM PB 0.15 M NaCl 30 mM imidazole PH 8.0 eluent 1; 7. 20 mM PB 0.15 M NaCl 30 mM imidazole PH 8.0 eluent 2; 8. 20 mM PB 0.15 M NaCl 30 mM imidazole PH 8.0 eluent 3; 9. 20 mM PB 0.15 M NaCl 30 mM imidazole PH 8.0 eluent 4