Peptidases, also known as proteases or proteinases, are enzymes that break down proteins into smaller peptides or amino acids. They play a crucial role in various biological processes, including digestion, cell signaling, and protein recycling. Peptidases can be classified based on their structure and mechanism of action, with categories such as serine, cysteine, and metallopeptidases. These enzymes are found in all living organisms, from bacteria to humans. In the human body, peptidases are essential for digesting dietary proteins, allowing the absorption of amino acids necessary for growth and repair. They also regulate many physiological functions by activating or deactivating other proteins, contributing to overall health.