Fig. 6.

Detection of CELA3B mutant E154K by the ScheBo Pancreatic Elastase 1 Stool Test. A: purified wild-type and E154K mutant CELA3B were assayed at 20–200 pM. B: purified wild-type and E154K mutant CELA3B were immobilized through their COOH-terminal His tags to Ni-NTA HisSorb plates (Qiagen) and detected with the biotinylated antibody-streptavidin-peroxidase complex from the ScheBo test. Assays were performed in duplicate, and both data points were plotted. C: structural model of human CELA3B indicating the positions of Glu¹⁵⁴ (green) and nearby Leu¹⁷⁹ (red). Also shown for reference are residues of the catalytic triad (magenta). Structural model for active CELA3B was generated by the SWISS-MODEL protein structure homology-modeling server (2) with porcine elastase used as template (PDB file 3UOU). Image was rendered with PyMOL (Schrödinger, Cambridge, MA).