Protein enzymes are not like casein, bacterial walls, parasitic protective films or even soya and gelatine proteins. These are catalysts which literally increase the speed of the chemical process that would make absorption and digestion as well as cleansing of the body possible.
Long chains of amino acids held together by peptide bonds are what consist of enzymes which are proteins too. They are found in all living things where they perform a large role in the metabolic process of any living organism. This is the only way that the nutrients from ingested foods are broken down into tiny particles and converted into the energy that the body needs as well as becoming fresh material for cells reproduced.