Aspartic peptidases are a group of enzymes that play a crucial role in protein digestion. They are characterized by their ability to cleave peptide bonds in proteins, specifically at the carboxyl side of aspartic acid residues. These enzymes are found in various organisms, including humans, where they contribute to processes such as digestion and immune response. These enzymes require an acidic environment to function effectively, which is why they are often active in the stomach. Examples of aspartic peptidases include pepsin, which is essential for breaking down food proteins, and renin, involved in blood pressure regulation.