Recall that proline often introduces kinks in the backbone of a polypeptide. These kinks make it difficult for enzymes in your gut to fully digest gluten. In people with celiac disease, certain proline-rich peptides left over after gluten digestion will trigger an abnormal immune response. Researchers have identified a mold enzyme called AN-PEP that effectively digests proline-rich peptides. Predict where the structural differences would occur between AN-PEP and other enzymes that do not digest the peptides. Select all that apply.

A) Amino acid differences would be expected in the site where it binds to bacterial cells or viruses.

B) Amino acid differences would be expected in the active site.

C) Amino acid differences would be expected in the gluten proteins that AN-PEP would be able to digest.

D) Amino acid differences would be expected in regions that affect the folded structure of the active site.

E) Amino acid differences would not be expected. The effectiveness of digestion depends on other conditions.