BioCoreDPP IV Helps Digest Gluten and Cereal Grains Gluten Digest, with BioCore DPP IV, is a comprehensive enzyme blend formulated to promote the complete digestion of cereal grains. DPP IV (Dipeptidyl peptidase IV) is a unique enzyme with specific activity against the characteristic proline bonds found in cereal grain proteins. Gluten Digest also includes proteases and amylases that address other protein and carbohydrate components that commonly co-occur in these foods.