Purity >95%, by SDS-PAGE visualized with Silver Staining and quantitative densitometry by Coomassie? Blue Staining. MW (observed): 84-103 kDa, reducing conditions. MW (theoretical): 75 kDa. The Recombinant Human KAL1 Protein from R&D Systems is derived from CHO. The Recombinant Human KAL1 Protein has been validated for the following applications: Bioactivity.