FGF-2 species-matched kit (Qk501)

Protein background

Fibroblast growth factor 2 (FGF-2) – also known as basic fibroblast growth factor (bFGF) – has a broad range of physiological roles, including regulation of cell proliferation and differentiation. FGF-2 is used to support the maintenance of embryonic stem cells and proliferation and differentiation of induced pluripotent and mesenchymal stem cells [1-3].

FGF-2 is inherently unstable and prone to proteolytic degradation and aggregation. This fundamental biochemical instability, and therefore low half-life in culture media (<10 h), is an important contribution to the need for frequent media changes and challenges in improving homogeneity during stem cell proliferation and subsequent differentiation. To improve the stability of FGF-2 for stem cell and cultivated meat applications, an optimal set of nine amino acid substitutions that stabilize FGF-2 were identified. The biological activity of wild-type FGF-2 is <50% after 10h incubation with conditioned media. In contrast, no reduction in FGF2-G3 biological activity is observed after >7 days incubation with conditioned media at 37 ^oC.

It is generally accepted that best practice is to use growth factors from the target species for reasons of consumer acceptance, regulatory considerations and species-matched activity including differences in receptor binding and efficacy in some cases. Some growth factor protein sequences are highly conserved and 100% identical across species. There is currently a lack of commercial availability of cultured-meat and fish relevant species-matched growth factors, so often human proteins, or indeed bovine serum, are used as a surrogate. It’s advisable to determine the conservation of protein sequence when selecting appropriate growth factors and switch to species-matched proteins if feasible.