Proteases 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 the immune response. By cleaving the peptide bonds that link amino acids, proteases help the body utilize proteins from food and regulate protein functions within cells. These enzymes are classified into different categories based on their active site and mechanism of action, such as serine proteases, cysteine proteases, and metalloproteases. Proteases are found in all living organisms, from bacteria to humans, and are essential for maintaining cellular health and function.