Fig. 4.

Characterization of soluble non-activated and protease activated pro-Affibody. a Representative SDS-PAGE of non-activated (1) and activated pro-Affibody (2). M represents molecular weight marker with indicated sizes in kDa. Protein production, purification, enzymatic hydrolysis and SDS-PAGE analysis was performed in duplicates on different days. b Representative sensorgram from Biacore experiments with HER2 immobilized on the chip surface. The response from 100 nM of the activated (green) and non-activated pro-Affibody (red) was compared to the HER2-binding Affibody molecule (Z_HER2) (blue) and the two non-fused monomeric domains of the pro-Affibody molecule mixed in an equimolar ratio (black). c Representative sensorgram from Biacore experiments with HER2 immobilized on the chip surface. The response from 100, 300 and 900 nM of the activated (green) and non-activated pro-Affibody (red). All biosensor experiments were performed at least in duplicates using freshly prepared samples and reagents