Proteolysis, the cleavage of peptide bonds between amino acids, is achieved by enzymes termed proteases. These include aspartic proteases, cysteine proteases, serine proteases and metalloproteases. Protease activity is central to diverse physiological cascades throughout biology. Aspartic proteases include beta and gamma secretases, the two enzymes necessary to release amyloid beta peptides from the Alzheimer's disease associated amyloid precursor protein (APP). Cysteine proteases include caspases which are involved in apoptosis and inflammation, and cathepsins which promote protein degradation. The Metalloprotease family includes aminopeptidases and endopeptidases, which are secreted, membrane-bound, or cytosolic. Serine proteases display a wide range of functions. Some are essential for coagulation, while others contribute to cancer pathology. R&D Systems offers a broad selection of products for proteases and modulators of protease activity.