Gluten is a mixture of proteins abundant in wheat, barley, and rye. Although these grains are staples in the Western diet, almost 1 percent of Americans have celiac disease- a disorder of the intestines caused by an abnormal immune response after eating gluten. This immune response damages the fingerlike villi of the small intestine, which can lead to intestinal upset and malnourishment. Currently, the only treatment is to maintain a strict gluten-free diet.
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.