Purity >90%, by SDS-PAGE visualized with Silver Staining and quantitative densitometry by Coomassie? Blue Staining. MW (observed): 150-175 kDa, reducing conditions. MW (theoretical): 125 kDa. The Recombinant Human Fibulin 2 Protein from R&D Systems is derived from HEK293. The Recombinant Human Fibulin 2 Protein has been validated for the following applications: Bioactivity.