![Tetrapeptide structural formulae v](https://upload.wikimedia.org/wikipedia/commons/0/08/Tetrapeptide_structural_formulae_v.1.png)
Peptides (, ) are short chains of
amino acid
Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha am ...
s linked by
peptide bond
In organic chemistry, a peptide bond is an amide type of covalent chemical bond linking two consecutive alpha-amino acids from C1 (carbon number one) of one alpha-amino acid and N2 (nitrogen number two) of another, along a peptide or protein cha ...
s. Long chains of amino acids are called
proteins
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...
. Chains of fewer than twenty amino acids are called
oligopeptides, and include
dipeptide A dipeptide is an organic compound derived from two amino acids. The constituent amino acids can be the same or different. When different, two isomers of the dipeptide are possible, depending on the sequence. Several dipeptides are physiologicall ...
s,
tripeptides, and
tetrapeptides.
A polypeptide is a longer, continuous, unbranched peptide chain.
Hence, peptides fall under the broad chemical classes of
biological polymers and
oligomer
In chemistry and biochemistry, an oligomer () is a molecule that consists of a few repeating units which could be derived, actually or conceptually, from smaller molecules, monomers.Quote: ''Oligomer molecule: A molecule of intermediate relativ ...
s, alongside
nucleic acid
Nucleic acids are biopolymers, macromolecules, essential to all known forms of life. They are composed of nucleotides, which are the monomers made of three components: a 5-carbon sugar, a phosphate group and a nitrogenous base. The two main cl ...
s,
oligosaccharide
An oligosaccharide (/ˌɑlɪgoʊˈsækəˌɹaɪd/; from the Greek ὀλίγος ''olígos'', "a few", and σάκχαρ ''sácchar'', "sugar") is a saccharide polymer containing a small number (typically two to ten) of monosaccharides (simple sugar ...
s,
polysaccharide
Polysaccharides (), or polycarbohydrates, are the most abundant carbohydrates found in food. They are long chain polymeric carbohydrates composed of monosaccharide units bound together by glycosidic linkages. This carbohydrate can react with wa ...
s, and others.
A polypeptide that contains more than approximately 50 amino acids is known as a
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...
.
Proteins consist of one or more polypeptides arranged in a biologically functional way, often bound to
ligand
In coordination chemistry, a ligand is an ion or molecule (functional group) that binds to a central metal atom to form a coordination complex. The bonding with the metal generally involves formal donation of one or more of the ligand's electr ...
s such as
coenzyme
A cofactor is a non-protein chemical compound or metallic ion that is required for an enzyme's role as a catalyst (a catalyst is a substance that increases the rate of a chemical reaction). Cofactors can be considered "helper molecules" that ass ...
s and
cofactors, or to another protein or other
macromolecule
A macromolecule is a very large molecule important to biophysical processes, such as a protein or nucleic acid. It is composed of thousands of covalently bonded atoms. Many macromolecules are polymers of smaller molecules called monomers. The ...
such as
DNA or
RNA
Ribonucleic acid (RNA) is a polymeric molecule essential in various biological roles in coding, decoding, regulation and expression of genes. RNA and deoxyribonucleic acid ( DNA) are nucleic acids. Along with lipids, proteins, and carbohydra ...
, or to complex
macromolecular assemblies
The term macromolecular assembly (MA) refers to massive chemical structures such as viruses and non-biologic nanoparticles, cellular organelles and membranes and ribosomes, etc. that are complex mixtures of polypeptide, polynucleotide, polysaccha ...
.
Amino acids that have been incorporated into peptides are termed
residues. A water molecule is released during formation of each
amide
In organic chemistry, an amide, also known as an organic amide or a carboxamide, is a compound with the general formula , where R, R', and R″ represent organic groups or hydrogen atoms. The amide group is called a peptide bond when it is ...
bond.
[.] All peptides except
cyclic peptide
Cyclic peptides are polypeptide chains which contain a circular sequence of bonds. This can be through a connection between the amino and carboxyl ends of the peptide, for example in cyclosporin; a connection between the amino end and a side chai ...
s have an
N-terminal
The N-terminus (also known as the amino-terminus, NH2-terminus, N-terminal end or amine-terminus) is the start of a protein or polypeptide, referring to the free amine group (-NH2) located at the end of a polypeptide. Within a peptide, the ami ...
(amine group) and
C-terminal (carboxyl group) residue at the end of the peptide (as shown for the tetrapeptide in the image).
Classes
There are numerous types of peptides that have been classified according to their sources and functions. According to the Handbook of Biologically Active Peptides, some groups of peptides include plant peptides, bacterial/
antibiotic peptides, fungal peptides, invertebrate peptides, amphibian/skin peptides, venom peptides, cancer/anticancer peptides, vaccine peptides, immune/inflammatory peptides, brain peptides,
endocrine peptides, ingestive peptides, gastrointestinal peptides, cardiovascular peptides, renal peptides, respiratory peptides,
opiate peptides,
neurotrophic
Neurotrophic factors (NTFs) are a family of biomolecules – nearly all of which are peptides or small proteins – that support the growth, survival, and differentiation of both developing and mature neurons. Most NTFs exert their trop ...
peptides, and blood–brain peptides.
Some ribosomal peptides are subject to
proteolysis
Proteolysis is the breakdown of proteins into smaller polypeptides or amino acids. Uncatalysed, the hydrolysis of peptide bonds is extremely slow, taking hundreds of years. Proteolysis is typically catalysed by cellular enzymes called protease ...
. These function, typically in higher organisms, as
hormone
A hormone (from the Greek participle , "setting in motion") is a class of signaling molecules in multicellular organisms that are sent to distant organs by complex biological processes to regulate physiology and behavior. Hormones are required ...
s and signaling molecules. Some microbes produce peptides as
antibiotic
An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting bacterial infections, and antibiotic medications are widely used in the treatment and prevention of ...
s, such as
microcins and
bacteriocins.
Peptides frequently have
post-translational modification
Post-translational modification (PTM) is the covalent and generally enzymatic modification of proteins following protein biosynthesis. This process occurs in the endoplasmic reticulum and the golgi apparatus. Proteins are synthesized by ribosome ...
s such as
phosphorylation
In chemistry, phosphorylation is the attachment of a phosphate group to a molecule or an ion. This process and its inverse, dephosphorylation, are common in biology and could be driven by natural selection. Text was copied from this source, wh ...
,
hydroxylation
In chemistry, hydroxylation can refer to:
*(i) most commonly, hydroxylation describes a chemical process that introduces a hydroxyl group () into an organic compound.
*(ii) the ''degree of hydroxylation'' refers to the number of OH groups in a ...
,
sulfonation,
palmitoylation
Palmitoylation is the covalent attachment of fatty acids, such as palmitic acid, to cysteine (''S''-palmitoylation) and less frequently to serine and threonine (''O''-palmitoylation) residues of proteins, which are typically lipid bilayer, memb ...
, glycosylation, and
disulfide formation. In general, peptides are linear, although
lariat structures have been observed. More exotic manipulations do occur, such as racemization of L-amino acids to D-amino acids in
platypus venom.
''
Nonribosomal peptide Nonribosomal peptides (NRP) are a class of peptide secondary metabolites, usually produced by microorganisms like bacteria and fungi. Nonribosomal peptides are also found in higher organisms, such as nudibranchs, but are thought to be made by bacter ...
s'' are assembled by
enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. A ...
s, not the ribosome. A common non-ribosomal peptide is
glutathione, a component of the
antioxidant
Antioxidants are compounds that inhibit oxidation, a chemical reaction that can produce free radicals. This can lead to polymerization and other chain reactions. They are frequently added to industrial products, such as fuels and lubricant ...
defenses of most aerobic organisms.
Other nonribosomal peptides are most common in
unicellular organism
A unicellular organism, also known as a single-celled organism, is an organism that consists of a single cell, unlike a multicellular organism that consists of multiple cells. Organisms fall into two general categories: prokaryotic organisms and ...
s,
plant
Plants are predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae exclud ...
s, and
fungi
A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from ...
and are synthesized by
modular
Broadly speaking, modularity is the degree to which a system's components may be separated and recombined, often with the benefit of flexibility and variety in use. The concept of modularity is used primarily to reduce complexity by breaking a sy ...
enzyme complexes called ''nonribosomal peptide synthetases''.
These complexes are often laid out in a similar fashion, and they can contain many different modules to perform a diverse set of chemical manipulations on the developing product. These peptides are often
cyclic
Cycle, cycles, or cyclic may refer to:
Anthropology and social sciences
* Cyclic history, a theory of history
* Cyclical theory, a theory of American political history associated with Arthur Schlesinger, Sr.
* Social cycle, various cycles in soc ...
and can have highly complex cyclic structures, although linear nonribosomal peptides are also common. Since the system is closely related to the machinery for building
fatty acid
In chemistry, particularly in biochemistry, a fatty acid is a carboxylic acid with an aliphatic chain, which is either saturated or unsaturated. Most naturally occurring fatty acids have an unbranched chain of an even number of carbon atoms, fr ...
s and
polyketides, hybrid compounds are often found. The presence of
oxazoles or
thiazoles often indicates that the compound was synthesized in this fashion.
' are derived from animal milk or meat digested by
proteolysis
Proteolysis is the breakdown of proteins into smaller polypeptides or amino acids. Uncatalysed, the hydrolysis of peptide bonds is extremely slow, taking hundreds of years. Proteolysis is typically catalysed by cellular enzymes called protease ...
. In addition to containing small peptides, the resulting material includes fats, metals, salts, vitamins, and many other biological compounds. Peptones are used in nutrient media for growing bacteria and fungi.
''Peptide fragments'' refer to fragments of proteins that are used to identify or quantify the source protein. Often these are the products of enzymatic degradation performed in the laboratory on a controlled sample, but can also be forensic or paleontological samples that have been degraded by natural effects.
Chemical synthesis
Example families
The peptide families in this section are ribosomal peptides, usually with hormonal activity. All of these peptides are synthesized by cells as longer "propeptides" or "proproteins" and truncated prior to exiting the cell. They are released into the bloodstream where they perform their signaling functions.
Antimicrobial peptides
*
Magainin family
*
Cecropin
Cecropins are antimicrobial peptides. They were first isolated from the hemolymph of ''Hyalophora cecropia'', whence the term cecropin was derived. Cecropins lyse bacterial cell membranes; they also inhibit proline uptake and cause leaky membranes ...
family
*
Cathelicidin family
*
Defensin
Defensins are small cysteine-rich cationic proteins across cellular life, including vertebrate
Vertebrates () comprise all animal taxa within the subphylum Vertebrata () ( chordates with backbones), including all mammals, birds, reptiles, ...
family
Tachykinin peptides
*
Substance P
*
Kassinin
Kassinin is a peptide derived from the Kassina frog. It belongs to tachykinin family of neuropeptides. It is secreted as a defense response, and is involved in neuropeptide signalling.
The amino acid sequence is H-Asp-Val-Pro-Lys-Ser-Asp-Gln-Phe ...
*
Neurokinin A
Neurokinin A (NKA), formerly known as Substance K, is a neurologically active peptide translated from the pre-protachykinin gene. Neurokinin A has many excitatory effects on mammalian nervous systems and is also influential on the mammalian inflam ...
*
Eledoisin
Eledoisin is an undecapeptide of mollusk origin, belonging to the tachykinin family of neuropeptides.
It was first isolated from the posterior salivary glands of two mollusk species ''Eledone muschata'' and ''Eledone aldovandi'', which belong to ...
*
Neurokinin B
Vasoactive intestinal peptides
*
VIP (''Vasoactive Intestinal Peptide''; PHM27)
*
PACAP
Pituitary adenylate cyclase-activating polypeptide also known as PACAP is a protein that in humans is encoded by the ''ADCYAP1'' gene. pituitary adenylate cyclase-activating polypeptide is similar to vasoactive intestinal peptide. One of its effect ...
''Pituitary Adenylate Cyclase Activating Peptide''
*
Peptide PHI Peptide PHI, also known as peptide histidine isoleucine, is a peptide which functions as a hormone. This peptide contains a composition of 27 amino acids with histidine on the N-terminus and isoleucine on the C-terminus. It was originally isolated f ...
27 (''Peptide Histidine Isoleucine 27'')
*
GHRH 1-24 ''(Growth Hormone Releasing Hormone 1-24)''
*
Glucagon
Glucagon is a peptide hormone, produced by alpha cells of the pancreas. It raises concentration of glucose and fatty acids in the bloodstream, and is considered to be the main catabolic hormone of the body. It is also used as a Glucagon (medicati ...
*
Secretin
Secretin is a hormone that regulates water homeostasis throughout the body and influences the environment of the duodenum by regulating secretions in the stomach, pancreas, and liver. It is a peptide hormone produced in the S cells of the duode ...
Pancreatic polypeptide-related peptides
*
NPY NPY may refer to:
*Neuropeptide Y
Neuropeptide Y (NPY) is a 36 amino-acid neuropeptide that is involved in various physiological and homeostatic processes in both the central and peripheral nervous systems. NPY has been identified as the most ...
''(NeuroPeptide Y)
*
PYY
Peptide YY (PYY) also known as peptide tyrosine tyrosine is a peptide that in humans is encoded by the gene. Peptide YY is a short (36-amino acid) peptide released from cells in the ileum and colon (anatomy), colon in response to feeding. In t ...
''(Peptide YY)''
* APP ''(Avian Pancreatic Polypeptide)''
*
PPY ''Pancreatic PolYpeptide''
Opioid peptides
*
Proopiomelanocortin
Pro-opiomelanocortin (POMC) is a precursor polypeptide with 241 amino acid residues. POMC is synthesized in corticotrophs of the anterior pituitary from the 267-amino-acid-long polypeptide precursor pre-pro-opiomelanocortin (pre-POMC), by the r ...
(POMC) peptides
*
Enkephalin
An enkephalin is a pentapeptide involved in regulating nociception in the body. The enkephalins are termed endogenous ligands, as they are internally derived and bind to the body's opioid receptors. Discovered in 1975, two forms of enkephalin ...
pentapeptides
*
Prodynorphin peptides
Calcitonin peptides
*
Calcitonin
Calcitonin is a 32 amino acid peptide hormone secreted by parafollicular cells (also known as C cells) of the thyroid (or endostyle) in humans and other chordates. in the ultimopharyngeal body. It acts to reduce blood calcium (Ca2+), opposing the ...
*
Amylin
*
AGG01
AGG01 a peptide antibiotic discovered in the breast milk of the Tammar wallaby, reportedly one hundred times more powerful than penicillin ''in vitro''.
This compound was found to be effective against MRSA, '' E. coli'', ''Streptococci'', ''Salm ...
Self-assembling peptides
*
Aromatic short peptides
In chemistry, aromaticity is a chemical property of cyclic compound, cyclic (ring (chemistry), ring-shaped), ''typically'' plane (geometry), planar (flat) molecular structures with pi bonds in Resonance (chemistry), resonance (those containing ...
*
Biomimetic peptides
*
Peptide amphiphile
Peptide amphiphiles (PAs) are peptide-based molecules that self-assemble into supramolecular nanostructures including; spherical micelles, twisted ribbons, and high-aspect-ratio nanofibers. A peptide amphiphile typically comprises a hydrophilic pe ...
s
*Peptide dendrimers
Other peptides
*
B-type Natriuretic Peptide (BNP) - produced in the myocardium and useful in medical diagnosis
*
Lactotripeptides Lactotripeptides are two naturally occurring milk peptides: Isoleucine-Proline-Proline (IPP) and Valine-Proline-Proline (VPP). These lactotripeptides are derived from casein, which is a milk protein also found in dairy products. Although most norma ...
- Lactotripeptides might reduce
blood pressure
Blood pressure (BP) is the pressure of circulating blood against the walls of blood vessels. Most of this pressure results from the heart pumping blood through the circulatory system. When used without qualification, the term "blood pressure" r ...
, although the evidence is mixed.
* Peptidic components from traditional Chinese medicine Colla Corii Asini in hematopoiesis.
Terminology
Length
Several terms related to peptides have no strict length definitions, and there is often overlap in their usage:
* A ''polypeptide'' is a single linear chain of many amino acids (any length), held together by
amide bond
In organic chemistry, an amide, also known as an organic amide or a carboxamide, is a compound with the general formula , where R, R', and R″ represent organic groups or hydrogen atoms. The amide group is called a peptide bond when it is p ...
s.
* A ''
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...
'' consists of one or more polypeptides (more than about 50 amino acids long).
* An ''
oligopeptide'' consists of only a few amino acids (between two and twenty).
Number of amino acids
![Tripeptide Val-Gly-Ala Formula V1](https://upload.wikimedia.org/wikipedia/commons/d/d6/Tripeptide_Val-Gly-Ala_Formula_V1.svg)
Peptides and proteins are often described by the number of amino acids in their chain, e.g. a protein with 158 amino acids may be described as a "158 amino-acid-long protein".
Peptides of specific shorter lengths are named using
IUPAC numerical multiplier
The numerical multiplier (or multiplying affix) in IUPAC nomenclature indicates how many particular atoms or functional groups are attached at a particular point in a molecule. The affixes are derived from both Latin and Greek.
Compound affixes ...
prefixes:
* A ''
monopeptide'' has one amino acid.
* A ''
dipeptide A dipeptide is an organic compound derived from two amino acids. The constituent amino acids can be the same or different. When different, two isomers of the dipeptide are possible, depending on the sequence. Several dipeptides are physiologicall ...
'' has two amino acids.
* A ''
tripeptide'' has three amino acids.
* A ''
tetrapeptide'' has four amino acids.
* A ''pentapeptide'' has five amino acids. (''e.g.'',
enkephalin
An enkephalin is a pentapeptide involved in regulating nociception in the body. The enkephalins are termed endogenous ligands, as they are internally derived and bind to the body's opioid receptors. Discovered in 1975, two forms of enkephalin ...
).
* A ''hexapeptide'' has six amino acids. (''e.g.'',
angiotensin IV
Angiotensin is a peptide hormone that causes vasoconstriction and an increase in blood pressure. It is part of the renin–angiotensin system, which regulates blood pressure. Angiotensin also stimulates the release of aldosterone from the adr ...
).
* A ''heptapeptide'' has seven amino acids. (''e.g.'',
spinorphin
Spinorphin is an endogenous, non-classical opioid peptide of the hemorphin family first isolated from the bovine spinal cord (hence the prefix ''spin''-) and acts as a regulator of the enkephalinases, a class of enzymes that break down endogeno ...
).
* An ''octapeptide'' has eight amino acids (''e.g.'',
angiotensin II
Angiotensin is a peptide hormone that causes vasoconstriction and an increase in blood pressure. It is part of the renin–angiotensin system, which regulates blood pressure. Angiotensin also stimulates the release of aldosterone from the adre ...
).
* A ''nonapeptide'' has nine amino acids (''e.g.'',
oxytocin
Oxytocin (Oxt or OT) is a peptide hormone and neuropeptide normally produced in the hypothalamus and released by the posterior pituitary. It plays a role in social bonding, reproduction, childbirth, and the period after childbirth. Oxytocin ...
).
* A ''decapeptide'' has ten amino acids (''e.g.'',
gonadotropin-releasing hormone
Gonadotropin-releasing hormone (GnRH) is a releasing hormone responsible for the release of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) from the anterior pituitary. GnRH is a tropic peptide hormone synthesized and released ...
and
angiotensin I
Angiotensin is a peptide hormone that causes vasoconstriction and an increase in blood pressure. It is part of the renin–angiotensin system, which regulates blood pressure. Angiotensin also stimulates the release of aldosterone from the adrena ...
).
* A ''undecapeptide'' has eleven amino acids (''e.g.'',
substance P).
The same words are also used to describe a group of residues in a larger polypeptide (''e.g.'',
RGD motif
Arginylglycylaspartic acid (RGD) is the most common peptide motif responsible for cell adhesion to the extracellular matrix (ECM), found in species ranging from ''Drosophila'' to humans. Cell adhesion proteins called integrins recognize and bind ...
).
Function
* A ''
neuropeptide
Neuropeptides are chemical messengers made up of small chains of amino acids that are synthesized and released by neurons. Neuropeptides typically bind to G protein-coupled receptors (GPCRs) to modulate neural activity and other tissues like the ...
'' is a peptide that is active in association with neural tissue.
* A ''
lipopeptide'' is a peptide that has a
lipid
Lipids are a broad group of naturally-occurring molecules which includes fats, waxes, sterols, fat-soluble vitamins (such as vitamins A, D, E and K), monoglycerides, diglycerides, phospholipids, and others. The functions of lipids include ...
connected to it, and ''
pepducin Pepducins are cell-penetrating peptides that act as intracellular modulators of signal transference from receptors to G proteins. Pepducins were first developed at the Tufts Medical Center laboratories of Dr. Athan Kuliopulos and Dr. Lidija Covic ...
s'' are lipopeptides that interact with GPCRs.
* A ''
peptide hormone'' is a peptide that acts as a
hormone
A hormone (from the Greek participle , "setting in motion") is a class of signaling molecules in multicellular organisms that are sent to distant organs by complex biological processes to regulate physiology and behavior. Hormones are required ...
.
* A
proteose
A proteose is any of various water-soluble compounds that are produced during in-vitro or in-vivo hydrolytic breakdown of proteins a little before producing amino acids. It forms after breaking down of polypeptides by proteases such as gastric pep ...
is a mixture of peptides produced by the hydrolysis of proteins. The term is somewhat archaic.
* A peptidergic agent (or drug) is a chemical which functions to directly modulate the peptide systems in the body or brain. An example is
opioidergics, which are
neuropeptidergic
Neuropeptidergic means "related to neuropeptides".
A neuropeptidergic agent (or drug) is a chemical which functions to directly modulate the neuropeptide systems in the body or brain. An example is opioidergics.
See also
* Adenosinergic
* Cannabi ...
s.
* A cell-penetrating peptide is a peptide able to penetrate the cell membrane.
See also
*
Acetyl hexapeptide-3
Acetyl hexapeptide-3 or acetyl hexapeptide-8 (sources differ) is a synthetic anti-wrinkle cosmetics ingredient. It is a peptide which is a fragment of SNAP-25, a substrate of botulinum toxin (''Botox''). Acetyl hexapeptide-8 is marketed as Argire ...
*
Beefy meaty peptide
Beefy meaty peptide, also known as delicious peptide and abbreviated as BMP, is an 8-amino acid long peptide that has been identified as giving a beefy flavour to foods in which it is present. It was isolated from beef soup by Yamasaki and Maekaw ...
*
Collagen hybridizing peptide, a short peptide that can bind to denatured collagen in tissues
*
Bis-peptide
*
CLE peptide
*
Epidermal growth factor
Epidermal growth factor (EGF) is a protein that stimulates cell growth and differentiation by binding to its receptor, EGFR. Human EGF is 6-k Da and has 53 amino acid residues and three intramolecular disulfide bonds.
EGF was originally descr ...
* ''
Journal of Peptide Science''
*
Lactotripeptides Lactotripeptides are two naturally occurring milk peptides: Isoleucine-Proline-Proline (IPP) and Valine-Proline-Proline (VPP). These lactotripeptides are derived from casein, which is a milk protein also found in dairy products. Although most norma ...
*
Micropeptide
*
Multifunctional peptide
A multifunctional peptide is a peptide which occurs when two genes band together. This process gives new properties to the polypeptide
Peptides (, ) are short chains of amino acids linked by peptide bonds. Long chains of amino acids are called ...
*
Neuropeptide
Neuropeptides are chemical messengers made up of small chains of amino acids that are synthesized and released by neurons. Neuropeptides typically bind to G protein-coupled receptors (GPCRs) to modulate neural activity and other tissues like the ...
*
Palmitoyl pentapeptide-4
Palmitoyl pentapeptide-4 (palmitoyl pentapeptide-3 before 2006) is a matrikine used in anti-wrinkle cosmetics. It was launched in 2000 as an active ingredient for the personal care industry under the trade name Matrixyl by the French cosmetic act ...
*
Pancreatic hormone
The pancreatic islets or islets of Langerhans are the regions of the pancreas that contain its endocrine (hormone-producing) cells, discovered in 1869 by German pathological anatomist Paul Langerhans. The pancreatic islets constitute 1–2% of ...
*
peptide spectral library
A peptide spectral library is a curated, annotated and non-redundant collection/database of LC-MS/MS peptide spectra. One essential utility of a peptide spectral library is to serve as consensus templates supporting the identification of peptide/p ...
*
Peptide synthesis
*
Peptidomimetics (such as
peptoid
Peptoids (root from the Greek language, Greek πεπτός, ''peptós'' "digested"; derived from πέσσειν, ''péssein'' "to digest" and the Greek-derived suffix -oid meaning "like, like that of, thing like a ______," ), or poly-''N''-substit ...
s and
β-peptides) to peptides, but with different properties.
*
Protein tag, describing addition of peptide sequences to enable protein isolation or detection
*
Replikins Replikins are a group of peptides, whose increase in concentration in virus or other organism proteins is associated with rapid replication. It is often measured in number of replikins per 100 amino acids. This particular group of peptides have bee ...
*
Ribosome
Ribosomes ( ) are macromolecular machines, found within all cells, that perform biological protein synthesis (mRNA translation). Ribosomes link amino acids together in the order specified by the codons of messenger RNA (mRNA) molecules to ...
*
Translation (biology)
In molecular biology and genetics, translation is the process in which ribosomes in the cytoplasm or endoplasmic reticulum synthesize proteins after the process of transcription (biology), transcription of DNA to RNA in the cell's nucleus ( ...
References
{{Authority control
Peptides
Peptides (, ) are short chains of amino acids linked by peptide bonds. Long chains of amino acids are called proteins. Chains of fewer than twenty amino acids are called oligopeptides, and include dipeptides, tripeptides, and tetrapeptides.
A p ...