Serine proteases (SPs) are a family of proteases that utilize a uniquely activated serine residue in the substrate-binding pocket to catalytically hydrolyze peptide bonds. All of the serine proteases contain three residues at their active site: a serine, a histidine, and an aspartate. Serine proteases fall into two broad categories based on their structure: chymotrypsin-like (trypsin-like) or subtilisin-like. They are found ubiquitously in both eukaryotes and prokaryotes, and are the most widely studied group of proteins in biology. Because of Serine protesses are well-characterized, widespread and spectacularly diverse role in a host of physiological and pathological processes.
Serine proteases are involved in an enormous number of biological processes, as model enzymes for studying catalytic processes. In humans or mammals, Serine proteases are responsible for co-ordinating various physiological functions, especially in digestion, immune response, blood coagulation, and the complement system.
Members of the serine proteases are diverse with regard to their function, expression pattern and related to many diseases including cancer, arthritis, and emphysema. Some are active in the coagulation cascade and the complement pathways while others are found specifically in the granules of cytotoxic T lymphocytes and natural killer cells (Granzymes) or in mast cells with trypsin-like specificity (Tryptases). Secreted tissue Kallikreins are cancer markers while transmembrane proteases such as Corin and Enterokinase are convertases.