Fig. 6

Biological activity determination of hBMP-2 via induction of alkaline phosphatase activity in murine myoblastic C2C12 cells, reading at 405 nm after 72 h culture. Equations of the assay curves: for E. coli-derived hBMP-2 (GenScript): \({\text{Y}}_{{{\text{A4}}0 5}} = 0. 6 3 7 {\text{X}}_{{\upmu{\text{g}}/{\text{mL}}}} {-}0.0 1 1\left( {{\text{r}} = 0. 9 9 7;{\text{n}} = 5;{\text{P}} < 0.00 1} \right);{\text{ED}}_{ 50} = 2. 5 { }\upmu{\text{g}}\); for CHO-derived hBMP-2 (Infuse^®): \({\text{Y}}_{{{\text{A4}}0 5}} = 0. 6 8 2+ 1. 6 9 5 {\text{X}}_{{\upmu{\text{g}}/{\text{mL}}}} + 0. 2 60{\text{X}}^{ 2}_{{\upmu{\text{g}}/{\text{mL}}}} \left( {{\text{r}} = 0. 9 5 1;{\text{n}} = 7;{\text{P}} < 0.00 1} \right);{\text{ED}}_{ 50} = 0. 4 { }\upmu{\text{g}}\)