Purity >95%, by SDS-PAGE with silver staining. MW (observed): 18 kDa, reducing conditions. MW (theoretical): 16 kDa. The Recombinant Equine FGF basic/FGF2 Protein from R&D Systems is derived from E. coli. The Recombinant Equine FGF basic/FGF2 Protein has been validated for the following applications: Bioactivity.