I think your anwser would be all of the above but you don't have it
Answer:
Most peroxidases are ferric heme proteins; one notable exception being the glutathione peroxidase, which is a selenium-containing enzyme. They are present in virtually all living species.
Protein has many roles in your body. It helps repair and build your body's tissues, allows metabolic reactions to take place and coordinates bodily functions. In addition to providing your body with a structural framework, proteins also maintain proper pH and fluid balance.
I think it’s how they are inside and get stuck