Bioactivity was determined using a BMP-4-responsive firefly luciferase reporter assay in stably transfected HEK293T cells. Cells were treated with a serial dilution of BMP-4 for 6 hours in triplicate. Firefly luciferase activity was measured and normalized to the control, Renilla luciferase.
Bioactivity comparison between four independent lots of Qkine BMP-4 protein (Qk038), expressed in E. coli, shows a narrow bioactivity range of 17-34 pM.
The bioactivity of all newly manufactured lots of Qkine proteins are tested against previous lots. Exceptional lot-to-lot consistency of growth factors can contribute to an increased reproducibility in cell culture.