Proteases

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.

Trypsin is a type of serine protease enzyme from the PA clan superfamily found in the digestive system of many vertebrates, where it begins the digestion of proteins by hydrolysis, cutting long chains of amino acids into smaller pieces. Trypsin is formed in the small intestine when its proenzyme, known as trypsinogen and produced by the pancreas, is activated. Trypsin cuts peptide chains mainly at the carboxyl side of the amino acids lysine and arginine. It is widely used in numerous biotechnology applications in clinical and research laboratories. The enzymatic action of trypsin is commonly r

thumb|250px|Ribbon diagram of a protease ([[TEV protease) complexed with its peptide substrate in black with catalytic residues in red ()]] A protease (also called a peptidase, proteinase, or proteolytic enzyme) is an enzyme that catalyzes proteolysis, breaking down proteins into smaller polypeptides or single amino acids, and spurring the formation of new protein products. They do this by cleaving the peptide bonds within proteins by hydrolysis, a reaction where water breaks bonds. Proteases are involved in numerous biological pathways, including digestion of ingested proteins, protein catabo

mammalian protein found in Homo sapiens

Chymotrypsin (, chymotrypsins A and B, alpha-chymar ophth, avazyme, chymar, chymotest, enzeon, quimar, quimotrase, alpha-chymar, alpha-chymotrypsin A, alpha-chymotrypsin) is a digestive enzyme component of pancreatic juice acting in the duodenum, where it performs proteolysis, the breakdown of proteins and polypeptides. Chymotrypsin preferentially cleaves peptide amide bonds where the side chain of the amino acid N-terminal to the scissile amide bond (the P1 position) is a large hydrophobic amino acid (tyrosine, tryptophan, and phenylalanine). These amino acids contain an aromatic ring in thei

Caspases (cysteine-aspartic proteases, cysteine aspartases or cysteine-dependent aspartate-directed proteases) are a family of protease enzymes playing essential roles in programmed cell death. They are named caspases due to their specific cysteine protease activity – a cysteine in its active site nucleophilically attacks and cleaves a target protein only after an aspartic acid residue. As of 2009, there are 12 confirmed caspases in humans and 10 in mice, carrying out a variety of cellular functions.

Papain, also known as papaya proteinase I, is a cysteine protease () enzyme present in papaya (Carica papaya) and mountain papaya (Vasconcellea cundinamarcensis). It is the namesake member of the papain-like protease family.

thumb|right|Space-filling model of elastase thumb|200px|Crystals of porcine elastase

class of enzymes

class of enzymes

A metalloproteinase, or metalloprotease, is any protease enzyme whose catalytic mechanism involves a metal. An example is ADAM12 which plays a significant role in the fusion of muscle cells during embryo development, in a process known as myogenesis.

class of enzymes

Cathepsins (Ancient Greek kata- 'down' and hepsein 'boil'; abbreviated CTS) are proteases (enzymes that degrade proteins) found in all animals as well as other organisms. There are approximately a dozen members of this family, which are distinguished by their structure, catalytic mechanism, and which proteins they cleave. Most of the members become activated at the low pH found in lysosomes. Thus, the activity of this family lies almost entirely within those organelles. There are, however, exceptions such as cathepsin K, which works extracellularly after secretion by osteoclasts in bone resorp

mammalian protein found in Homo sapiens

protein-coding gene in the species Homo sapiens

protein-coding gene in the species Homo sapiens

protein-coding gene in the species Homo sapiens

A calpain (; , ) is a protein belonging to the family of calcium-dependent, non-lysosomal cysteine proteases (proteolytic enzymes) expressed ubiquitously in mammals and many other organisms. Calpains constitute the C2 family of protease clan CA in the MEROPS database. The calpain proteolytic system includes the calpain proteases, the small regulatory subunit CAPNS1, also known as CAPN4, and the endogenous calpain-specific inhibitor, calpastatin.

MEROPS is an online database for peptidases (also known as proteases, proteinases and proteolytic enzymes) and their inhibitors. The classification scheme for peptidases was published by Rawlings & Barrett in 1993, and that for protein inhibitors by Rawlings et al. in 2004. The most recent version, MEROPS 12.5, was released in September 2023.

protein-coding gene in the species Homo sapiens

Thermolysin (, Bacillus thermoproteolyticus neutral proteinase, thermoase, thermoase Y10, TLN) is a thermostable neutral metalloproteinase enzyme produced by the Gram-positive bacteria Bacillus thermoproteolyticus. It requires one zinc ion for enzyme activity and four calcium ions for structural stability. Thermolysin specifically catalyzes the hydrolysis of peptide bonds containing hydrophobic amino acids. However thermolysin is also widely used for peptide bond formation through the reverse reaction of hydrolysis. Thermolysin is the most stable member of a family of metalloproteinases produc

protein-coding gene in the species Homo sapiens

protein-coding gene in the species Homo sapiens

protein-coding gene in the species Homo sapiens

protein-coding gene in the species Homo sapiens

protein-coding gene in the species Homo sapiens (Humans)

mammalian protein found in Homo sapiens

protein-coding gene in the species Homo sapiens

mammalian protein found in Homo sapiens

class of enzymes

highly specific protease

Calpastatin is a protein that in humans is encoded by the CAST gene.

Serratiopeptidase (Serratia E-15 protease, also known as serralysin, serrapeptase, serratiapeptase, serratia peptidase, serratio peptidase, or serrapeptidase) is a proteolytic enzyme (protease) produced by enterobacterium Serratia sp. E-15, now known as Serratia marcescens ATCC 21074. This microorganism was originally isolated in the late 1960s from silkworm (Bombyx mori L.) intestine. Serratiopeptidase is present in the silkworm intestine and allows the emerging moth to dissolve its cocoon. Serratiopeptase is produced by purification from culture of Serratia E-15 bacteria. It is a member of t

protein-coding gene in the species Homo sapiens

A Disintegrin and metalloproteinase domain-containing protein 10, also known as ADAM10 or CDw156 or CD156c, is a protein that in humans is encoded by the ADAM10 gene.

protein-coding gene in the species Homo sapiens

Kallikrein-1 is a protein that in humans is encoded by the KLK1 gene. KLK1 is a member of the peptidase S1 family.

protein-coding gene in the species Homo sapiens

A disintegrin and metalloprotease 17 (ADAM17), also called TACE (tumor necrosis factor-α-converting enzyme), is a 70-kDa enzyme that belongs to the ADAM protein family of disintegrins and metalloproteases, activated by substrate presentation.

protein-coding gene in the species Homo sapiens

class of enzymes

A Disintegrin and metalloproteinase domain-containing protein 8 is an enzyme that in humans is encoded by the ADAM8 gene.

class of enzymes

Disintegrin and metalloproteinase domain-containing protein 18 is an enzyme that in humans is encoded by the ADAM18 gene.

protein-coding gene in the species Homo sapiens

class of enzymes

ATP-dependent Clp protease ATP-binding subunit clpX-like, mitochondrial is an enzyme that in humans is encoded by the CLPX gene. This protein is a member of the family of AAA Proteins (AAA+ ATPase) and is to form the protein complex of Clp protease (Endopeptidase Clp).

protein-coding gene in the species Homo sapiens