EC 3.4.23

Pepsin is an endopeptidase that breaks down proteins into smaller peptides and amino acids. It is one of the main digestive enzymes in the digestive systems of humans and many other animals, where it helps digest the proteins in food. Pepsin is an aspartic protease, using a catalytic aspartate in its active site.

Renin (etymology and pronunciation), also known as an angiotensinogenase, is an aspartic protease protein and enzyme secreted by the kidneys that participates in the body's renin–angiotensin–aldosterone system (RAAS), which increases the volume of extracellular fluid (blood plasma, lymph, and interstitial fluid) and causes arterial vasoconstriction. Thus, it increases the body's mean arterial blood pressure.

thumb|right|Animal rennet to be used in the manufacture of cheddar cheese

Chymosin or rennin is a protease found in rennet. It is an aspartic endopeptidase belonging to MEROPS A1 family. It is produced by newborn ruminant animals in the lining of the abomasum to curdle the milk they ingest, allowing a longer residence in the bowels and better absorption. It is widely used in the production of cheese.

class of enzymes

mammalian protein found in Homo sapiens

class of enzymes

thumb|right|S. aureus uses coagulase to form a fibrin coat from fibrinogen present in the bloodstream. This helps the bacteria evade detection and phagocytosis by the immune system. Coagulase is a protein enzyme produced by several microorganisms that enables the conversion of fibrinogen to fibrin. In the laboratory, it is used to distinguish between different types of Staphylococcus isolates. Importantly, S. aureus is generally coagulase-positive, meaning that a positive coagulase test would indicate the presence of S. aureus or any of the other 11 coagulase-positive Staphylococci.

Trypsinogen () is the precursor form (or zymogen) of trypsin, a digestive enzyme. It is produced by the pancreas and found in pancreatic juice, along with amylase, lipase, and chymotrypsinogen. It is cleaved to its active form, trypsin, by enteropeptidase, which is found in the intestinal mucosa. Once activated, the trypsin can cleave more trypsinogen into trypsin, a process called autoactivation. Trypsin cleaves the peptide bond on the carboxyl side of basic amino acids such as arginine and lysine.

protein-coding gene in the species Homo sapiens

protein-coding gene in the species Homo sapiens

Progastricsin also known as pepsinogen C or pepsinogen II is a pepsinogen precursor of the enzyme gastricsin that in humans is encoded by the PGC gene.

thumb | right | alt=Leaf of a Drosera peltata with a captured ant. Royal National Park, NSW Australia, August 2011. | Leaf of a Drosera peltata with a captured ant. Royal National Park, NSW Australia, 2011. Nepenthesin (also spelled nepenthacin or nepenthasin) is an aspartic protease of plant origin that has so far been identified in the pitcher secretions of Nepenthes and in the leaves of Drosera peltata. It is similar to pepsin, but differs in that it also cleaves on either side of Asp residues and at Lys┼Arg. While more pH and temperature stable than porcine pepsin A, it is considerably le

enzyme responsible for maturing type 4 pilins

Endothiapepsin (, Endothia aspartic proteinase, Endothia acid proteinase, Endothia parasitica acid proteinase, Endothia parasitica aspartic proteinase) is an enzyme. This enzyme catalyses the following chemical reaction

protein-coding gene in the species Homo sapiens