2.By the assay of Bradford and Glyko BandScan, we detected that the yield of hBMP4 expressed in shaken flask was 33. 34 mg/L and amounted to 50. 4% of the total protein in the supernatant. The yield of hBMP7 was 13. 76 mg/L and amounted to 20. 8% of the total protein in the supernatant.