Campuran berbagai enzim yang menguraikan protein lebih jauh lagi setelah pepsin dan tripsin campuran enzim ini menyempurnakan penguraian protein menjadi asam-asam amino. Erepsin dihasilkan oleh kelenjar-kelenjar dalam dinding usus halus.
Erepsin is a protein fraction found in the intestinal juices and contains a group of enzymes that digest peptones into amino acids. It is produced and secreted by the intestinal glands in the ileum and the pancreas. It is also found widely in other cells. It is however a term now rarely used in scientific literature as more precise terms are preferred.