Proteolysis

proteolyticprotein degradationpolyproteindegradationproteolyticallyproteolytic degradationproteolytic processingproteolytic cleavagecleavedproteolyic
Proteolysis is the breakdown of proteins into smaller polypeptides or amino acids.wikipedia
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Protease

proteasespeptidaseproteinase
Proteolysis is typically catalysed by cellular enzymes called proteases, but may also occur by intra-molecular digestion.
A protease (also called a peptidase or proteinase) is an enzyme that catalyzes (increases the rate of) proteolysis, the breakdown of proteins into smaller polypeptides or single amino acids.

Protein biosynthesis

protein synthesissynthesissynthesized
Limited proteolysis of a polypeptide during or after translation in protein synthesis often occurs for many proteins.
Protein synthesis is the process whereby biological cells generate new proteins; it is balanced by the loss of cellular proteins via degradation or export.

Peptide

polypeptidepeptidespolypeptides
Proteolysis is the breakdown of proteins into smaller polypeptides or amino acids.
Some ribosomal peptides are subject to proteolysis.

N-end rule

In both prokaryotes and eukaryotes, the exposed N-terminal residue may determine the half-life of the protein according to the N-end rule. The N-end rule may partially determine the half-life of a protein, and proteins with segments rich in proline, glutamic acid, serine, and threonine (the so-called PEST proteins) have short half-life.
The N-end rule is a rule that governs the rate of protein degradation through recognition of the N-terminal residue of proteins.

Proteasome

proteasomalproteosomeproteasomes
The intracellular degradation of protein may be achieved in two ways - proteolysis in lysosome, or a ubiquitin-dependent process that targets unwanted proteins to proteasome.
Proteasomes are protein complexes which degrade unneeded or damaged proteins by proteolysis, a chemical reaction that breaks peptide bonds.

Ubiquitin

ubiquitinationubiquitylationubiquitinated
The intracellular degradation of protein may be achieved in two ways - proteolysis in lysosome, or a ubiquitin-dependent process that targets unwanted proteins to proteasome.
Ubiquitination affects proteins in many ways: it can mark them for degradation via the proteasome, alter their cellular location, affect their activity, and promote or prevent protein interactions.

Trypsin

trypticanti-tryptictrypsin serine proteases
Proteolysis of the zymogen yields an active protein; for example, when trypsinogen is cleaved to form trypsin, a slight rearrangement of the protein structure that completes the active site of the protease occurs, thereby activating the protein. In human digestion, proteins in food are broken down into smaller peptide chains by digestive enzymes such as pepsin, trypsin, chymotrypsin, and elastase, and into amino acids by various enzymes such as carboxypeptidase, aminopeptidase, and dipeptidase.
The process is commonly referred to as trypsin proteolysis or trypsinisation, and proteins that have been digested/treated with trypsin are said to have been trypsinized.

Chymotrypsin

Alpha Chymaralpha-chymotrypsinbovine alpha-chymotrypsin
In human digestion, proteins in food are broken down into smaller peptide chains by digestive enzymes such as pepsin, trypsin, chymotrypsin, and elastase, and into amino acids by various enzymes such as carboxypeptidase, aminopeptidase, and dipeptidase.
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.

Digestion

digestivedigestdigested
In human digestion, proteins in food are broken down into smaller peptide chains by digestive enzymes such as pepsin, trypsin, chymotrypsin, and elastase, and into amino acids by various enzymes such as carboxypeptidase, aminopeptidase, and dipeptidase.
Gastric juice in the stomach starts protein digestion.

Subtilisin

alcalasesavinasesubtilin
Subtilisin, which is produced by Bacillus subtilis, is produced as preprosubtilisin, and is released only if the signal peptide is cleaved and autocatalytic proteolytic activation has occurred.
Subtilisin is a non-specific protease (a protein-digesting enzyme) initially obtained from Bacillus subtilis.

Insulin

insulin geneINShuman insulin
Insulin, for example, is synthesized as preproinsulin, which yields proinsulin after the signal peptide has been cleaved.

Peptide bond

peptide bondsamide bondprotein backbone
Uncatalysed, the hydrolysis of peptide bonds is extremely slow, taking hundreds of years.
This is the pathway followed in proteolysis and, more generally, in N-O acyl exchange reactions such as those of inteins.

Protease inhibitor (biology)

protease inhibitorprotease inhibitorsproteinase inhibitor
Proteases may be regulated by antiproteases or protease inhibitors, and imbalance between proteases and antiproteases can result in diseases, for example, in the destruction of lung tissues in emphysema brought on by smoking tobacco.
In biology and biochemistry, protease inhibitors, or antiproteases, are molecules that inhibit the function of proteases (enzymes that aid the breakdown of proteins).

Hydrolysis

hydrolyzedhydrolysehydrolyze
Uncatalysed, the hydrolysis of peptide bonds is extremely slow, taking hundreds of years.

Serpin

serine protease inhibitorSerpinsserine protease inhibitors
Smoking is thought to increase the neutrophils and macrophages in the lung which release excessive amount of proteolytic enzymes such as elastase, such that they can no longer be inhibited by serpins such as α 1 -antitrypsin, thereby resulting in the breaking down of connective tissues in the lung.
Although most serpins control proteolytic cascades, some proteins with a serpin structure are not enzyme inhibitors, but instead perform diverse functions such as storage (as in egg white—ovalbumin), transport as in hormone carriage proteins (thyroxine-binding globulin, cortisol-binding globulin) and molecular chaperoning (HSP47).

Protein folding

foldfoldingfolded
Protein folding occurs in the single-chain Proinsulin form which facilitates formation of the ultimately inter-peptide disulfide bonds, and the ultimately intra-peptide disulfide bond, found in the native structure of insulin.
Proteolysis is routinely used to probe the fraction unfolded under a wide range of solution conditions (e.g. Fast parallel proteolysis (FASTpp).

Thrombin

prothrombinIIFactor II
Prothrombin (coagulation factor II) is proteolytically cleaved to form thrombin in the clotting process.

Alzheimer's disease

AlzheimerAlzheimer’s diseaseAlzheimer disease
Abnormal proteolysis and generation of peptides that aggregate in cells and their ineffective removal may result in many age-related neurological diseases such as Alzheimer's.
In Alzheimer's disease, gamma secretase and beta secretase act together in a proteolytic process which causes APP to be divided into smaller fragments.

PEST sequence

PESTPEST domainPEST hypothesis
The N-end rule may partially determine the half-life of a protein, and proteins with segments rich in proline, glutamic acid, serine, and threonine (the so-called PEST proteins) have short half-life.
This sequence is associated with proteins that have a short intracellular half-life; therefore, it is hypothesized that the PEST sequence acts as a signal peptide for protein degradation.

Apoptosis

apoptoticprogrammed cell deathcell death
Caspases are an important group of proteases involved in apoptosis or programmed cell death.
Effector caspases are then activated by these active initiator caspases through proteolytic cleavage.

Protein purification

purifiedpurificationisolate
If the protein of interest is sensitive to proteolysis, it is recommended to proceed quickly, and to keep the extract cooled, to slow down the digestion.

Protein

proteinsproteinaceousstructural proteins
Proteolysis is the breakdown of proteins into smaller polypeptides or amino acids.
Once formed, proteins only exist for a certain period and are then degraded and recycled by the cell's machinery through the process of protein turnover.

Threonine protease

threonine-threoninethreonines
Threonine proteases are a family of proteolytic enzymes harbouring a threonine (Thr) residue within the active site.

Glutamic protease

glutamic-
Glutamic proteases are a group of proteolytic enzymes containing a glutamic acid residue within the active site.

The Proteolysis Map

PMAP
PMAP is to aid the protease researchers in reasoning about proteolytic networks and metabolic pathways.