Bruger:Drlectin/sandkasse2

• Bruger:Drlectin/væsentligebidrag
• bruger:Drlectin/sandkasse
• Biokemi UNDER UDARBEJDELSE. Bruger:Drlectin/sandkasse1
• Hormoner og vækstfaktorer. UNDER UDARBEJDELSE Bruger:Drlectin/sandkasse3
• Trimer, IgSF, TMD. UNDER UDARBEJDELSE Bruger:Drlectin/sandkasse4
• Molekylær evolution UNDER UDARBEJDELSE bruger:Drlectin/sandkasse5
• Bruger:Drlectin/sandkasse6

Peptider

NYT OM PEPTIDER

Molecules similar to those produced by sea anemones are neuroprotective in a mouse cell model of Alzheimer’s disease.https://www.the-scientist.com/image-of-the-day/image-of-the-day--ocean-wonder-64745

Lasssopeptider http://pubs.acs.org/doi/abs/10.1021/acs.accounts.5b00156

Antimocrobial peptides http://www.sciencealert.com/the-science-world-s-freaking-out-over-this-25-year-old-s-solution-to-antibiotic-resistance

Peptider med Inhibitor cystine knot

Myotoxin

Peptide classes

Peptides are divided into several classes, depending on how they are produced:

Milk peptides

Two naturally occurring milk peptides are formed from the milk protein casein when digestive enzymes break this down; they can also arise from the proteinases formed by lactobacilli during the fermentation of milk.[4]

Ribosomal peptides

Ribosomal peptides are synthesized by translation of mRNA. They are often subjected to proteolysis to generate the mature form. These function, typically in higher organisms, as hormones and signaling molecules. Some organisms produce peptides as antibiotics, such as microcins.[5] Since they are translated, the amino acid residues involved are restricted to those utilized by the ribosome.

However, these peptides frequently have posttranslational modifications... such as phosphorylation, hydroxylation, sulfonation, palmitoylation, glycosylation and disulfide formation. In general, they are linear, although lariat structures have been observed.[6] More exotic manipulations do occur, such as racemization of L-amino acids to D-amino acids in platypus venom.[7]

Nonribosomal peptides

Nonribosomal peptides are assembled by enzymes that are specific to each peptide, rather than by the ribosome. The most common non-ribosomal peptide is glutathione, which is a component of the antioxidant defenses of most aerobic organisms.[8] Other nonribosomal peptides are most common in unicellular organisms, plants, and fungi and are synthesized by modular enzyme complexes called nonribosomal peptide synthetases.[9]

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.[10] These peptides are often cyclic 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 acids and polyketides, hybrid compounds are often found. The presence of oxazoles or thiazoles often indicates that the compound was synthesized in this fashion.[11]

Peptones

See also Tryptone

Peptones are derived from animal milk or meat digested by proteolysis.[12] In addition to containing small peptides, the resulting spray-dried material [clarification needed] includes fats, metals, salts, vitamins and many other biological compounds. Peptones are used in nutrient media for growing bacteria and fungi.[13]

Peptide fragments

Peptide fragments refer to fragments of proteins that are used to identify or quantify the source protein.[14] 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.[15][16]

Antibacterielle peptider

Venom peptoder http://science.sciencemag.org/content/361/6405/842?utm_source=sciencemagazine&utm_medium=facebook-text&utm_campaign=holford-21222

---

Well-known peptide 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.

Tachykinin peptides (neuropeptides)

Main article: Tachykinin peptides • Substance P • Kassinin • Neurokinin A • Eledoisin • Neurokinin B

Vasoactive intestinal peptides

Main article: Secretin family • VIP (Vasoactive Intestinal Peptide; PHM27) • PACAP Pituitary Adenylate Cyclase Activating Peptide • Peptide PHI 27 (Peptide Histidine Isoleucine 27) • GHRH 1-24 (Growth Hormone Releasing Hormone 1-24) • Glucagon • Secretin

Pancreatic polypeptide-related peptides

• NPY (NeuroPeptide Y) • PYY (Peptide YY) • APP (Avian Pancreatic Polypeptide) • PPY Pancreatic PolYpeptide

Opioid peptides

Main article: Opioid peptide • Proopiomelanocortin (POMC) peptides • Enkephalin pentapeptides • Prodynorphin peptides

Calcitonin peptides

• Calcitonin • Amylin • AGG01

Other peptides

• B-type Natriuretic Peptide (BNP) - produced in myocardium & useful in medical diagnosis Lactotripeptides - Lactotripeptides might reduce blood pressure,[21][22][23] although the evidence is mixed.[24]

Pancreatic peptide family

PP 36 as, 4200 Da

Relateret til peptide YY

NEUROPEPTIDES

https://en.wikipedia.org/wiki/Neuropeptide

• Neuropeptide Y increasing food intake and storage of energy as fat, reducing anxiety and stress, reducing pain perception, affecting the circadian rhythm, reducing voluntary alcohol intake, lowering blood pressure, and controlling epileptic seizures

36 as

Neuropeptide Y receptors are a class of G-protein coupled receptors which are activated by the closely related peptide hormones neuropeptide Y, peptide YY and pancreatic polypeptide.[1] These receptors are involved in the control of a diverse set of behavioral processes including appetite, circadian rhythm, and anxiety.

• Neuropeptide FF Neuropeptide FF (NPFF) and neuropeptide VF (NPVF) are octapeptides belonging to the RFamide family of peptides that have been implicated in a wide variety of physiological functions in the brain, including central autonomic and neuroendocrine regulation.

8 as

Receptors NPFF1 and NPFF2, G-protein coupled receptor superfamily of integral membrane proteins which bind the pain modulatory neuropeptides AF and FF

• Neuropeptid S

Neuropeptides are small protein-like molecules (peptides) used by neurons to communicate with each other. They are neuronal signaling molecules that influence the activity of the brain in specific ways. Different neuropeptides are involved in a wide range of brain functions, including analgesia, reward, food intake, metabolism, reproduction, social behaviors, learning and memory. Peptides can affect gene expression, local blood flow, synaptogenesis, and glial cell morphology. Peptides tend to have prolonged actions, and some have striking effects on behaviour.

In essence they act as specific signals between one population of neurons and another.

The human genome contains about 90 genes that encode precursors of neuropeptides. At present about 100 different peptides are known to be released by different populations of neurons in the mammalian brain.[2]

Neuropeptides are related to peptide hormones, and in some cases peptides that function in the periphery as hormones also have neuronal functions as neuropeptides. The distinction between neuropeptide and peptide hormone has to do with the cell types that release and respond to the molecule; neuropeptides are secreted from neuronal cells (primarily neurons but also glia for some peptides) and signal to neighboring cells (primarily neurons). In contrast, peptide hormones are secreted from neuroendocrine cells and travel through the blood to distant tissues where they evoke a response. Both neuropeptides and peptide hormones are synthesized by the same sets of enzymes, which include prohormone convertases and carboxypeptidases that selectively cleave the peptide precursor at specific processing sites to generate the bioactive peptides. [1]

Neuropeptides modulate neuronal communication by acting on cell surface receptors. Many neuropeptides are co-released with other small-molecule neurotransmitters. Neurons use many different chemical signals to communicate information, including neurotransmitters, peptides, and gasotransmitters.

Peptides are unique among these cell-cell signaling molecules in several respects. One major difference is that peptides are not recycled back into the cell once secreted, unlike many conventional neurotransmitters (glutamate, dopamine, serotonin). Another difference is that after secretion, peptides are modified by extracellular peptidases; in some cases, these extracellular cleavages inactivate the biological activity, but in other cases the extracellular cleavages increase the affinity of a peptide for a particular receptor while decreasing its affinity for another receptor. These extracellular processing events add to the complexity of neuropeptides as cell-cell signaling molecules.

Arcuate nucleus of the hypothalamus: Many populations of neurons have distinctive biochemical phenotypes. For example, in one subpopulation of about 3000 neurons in the arcuate nucleus of the hypothalamus, three anorectic peptides are co-expressed:

α-melanocyte-stimulating hormone (α-MSH),

galanin-like peptide, and

cocaine-and-amphetamine-regulated transcript (CART), and in another subpopulation two orexigenic peptides are co-expressed,

neuropeptide Y and

agouti-related peptide (AGRP).

These are not the only peptides in the arcuate nucleus;

β-endorphin,

dynorphin,

enkephalin,

galanin,

ghrelin,

growth-hormone releasing hormone,

neurotensin,

neuromedin U, and

somatostatin

are also expressed in subpopulations of arcuate neurons. These peptides are all released centrally and act on other neurons at specific receptors. The neuropeptide Y neurons also make the classical inhibitory neurotransmitter GABA.

• Nerve Growth Factor. nerve growth factor (NGF) neurotrophin.

peptid: the 2.5S, 26-kDa beta subunit; proNGF (NGF precursor 7S, 130-kDa complex of 3 proteins - Alpha-NGF, Beta-NGF, and Gamma-NGF (2:1:2 ratio).

tropomyosine receptor kinase A (TrkA) and low-affinity NGF receptor (LNGFR/p75NTR).

• Brain-derived neurotrophic factor, also known as BDNF, is a protein[2] that, in humans, is encoded by the BDNF gene.[3][4] BDNF is a member of the neurotrophin family of growth factors, which are related to the canonical Nerve Growth Factor. Neurotrophic factors are found in the brain and the periphery. Flere receptorer: Tropomyosin receptor kinase B = receptor tyrosine kinase.

Invertebrates also have many neuropeptides. CCAP has several functions including regulating heart rate, allatostatin and proctolin regulate food intake and growth, bursicon controls tanning of the cuticle and corazonin has a role in cuticle pigmentation and moulting.

Function: Peptide signals play a role in information processing that is different from that of conventional neurotransmitters, and many appear to be particularly associated with specific behaviours. For example, oxytocin and vasopressin have striking and specific effects on social behaviours, including maternal behaviour and pair bonding.

Generally, peptides act at metabotropic or G-protein-coupled receptors expressed by selective populations of neurons.

Neurotransmitters generally affect the excitability of other neurons, by depolarising them or by hyperpolarising them. Peptides have much more diverse effects; amongst other things, they can affect gene expression, local blood flow, synaptogenesis, and glial cell morphology. Peptides tend to have prolonged actions, and some have striking effects on behaviour.

Neurons very often make both a conventional neurotransmitter (such as glutamate, GABA or dopamine) and one or more neuropeptides. Peptides are generally packaged in large dense-core vesicles, and the co-existing neurotransmitters in small synaptic vesicles. The large dense-core vesicles are often found in all parts of a neuron, including the soma, dendrites, axonal swellings (varicosities) and nerve endings, whereas the small synaptic vesicles are mainly found in clusters at presynaptic locations.[citation needed]Release of the large vesicles and the small vesicles is regulated differently.

Examples

The following is a list of neuroactive peptides coexisting with other neurotransmitters. Transmitter names are shown in bold.

Norepinephrine (noradrenaline). In neurons of the A2 cell group in the nucleus of the solitary tract), norepinephrine co-exists with: • Galanin neuromodulator, hæmmer neurotransmitter frigivelse, involved in the modulation and inhibition of action potentials in neurons. 30 as. 3 GPCR • Enkephalin • Neuropeptide Y, neuromodulator,vasoconstrictor mange funktioner fødeindtag, fedme, 36 as, 5 typer af receptor rhodopsin like GPCR

GABA • SomatostatinSomatostatinSomatostatinSomatostatinSomatostatin (in the hippocampus) • Cholecystokinin • Neuropeptide Y (in the arcuate nucleus)

Acetylcholine • VIP • Substance P – se nedenfor

Dopamine • Cholecystokinin • Neurotensin • Glucagon-like peptide-1 (in the nucleus accumbens)

Epinephrine (adrenaline) • Neuropeptide Y • Neurotensin

Serotonin (5-HT = 5-Hydroxytryptamine, With the exception of the 5-HT3 receptor, a ligand-gated ion channel, all other 5-HT receptors are G-protein-coupled receptors) • Substance P, neuromodulator, 11 as (neurokinin 1 receptor (NK1-receptor, NK1R).[9] It belongs to the tachykinin receptor sub-family of GPCR) • TRH, Thyrotropin-releasing hormone (TRH), also called thyrotropin-releasing factor (TRF) or thyroliberin, is a releasing hormone, produced by the hypothalamus, 3 as, TRHR = GPCR • Enkephalin, opioid, pentapeptider, GPCR

Some neurons make several different peptides. For instance, Vasopressin co-exists with dynorphin and galanin in magnocellular neurons of the supraoptic nucleus and paraventricular nucleus, and with CRF (in parvocellular neurons of the paraventricular nucleus)

Oxytocin in the supraoptic nucleus co-exists with enkephalin, dynorphin, cocaine-and amphetamine regulated transcript (CART) and cholecystokinin.

TACHYKININ PEPTIDES

https://en.wikipedia.org/wiki/Tachykinin_peptides

-se også oversigtsartikel 2002: http://pharmrev.aspetjournals.org/content/54/2/285.long

• in neuronal cells: act as neurotransmitters / neuromodulators,
• in non neuronal cells (amphibian skin, Invertebrate Salivary Glands,): act as autocrine, paracrine, or endocrine regulators (vasodilators)

more than 40 members represents one of the largest, if not the largest, family in the peptide world. – C-term Meth- NH2 - with the classical C-terminal pentapeptide sequence Phe-(Tyr/Ile)-Gly- Leu-Met-NH2

Eksempler:

• SP=Substance P , intestine, paracrine hormone
• Neurokinin A=NKA
• Neurokinin B=NKB
• Physalaemin
• Kassinin
• locustatachykinins
• Callitachykinin II

-- Invertebrate tachykinin-like peptides are linear peptides with 8 to 15 amino acid residues with C-term Arg-NH2

• Moschatin=eledoisin pGlu-Pro-Ser-Lys-Asp-Ala-Phe-Ile-Gly-Leu-Met-NH2;
• Sialokinin I Asn-Thr-Gly-Asp-Lys-Phe-Tyr-Gly-Leu-Met-NH2;
• Sialokinin II, Asp-Thr-Gly-Asp-Lys-Phe-Tyr-Gly-Leu-Met-NH2.

--Submammalian Vertebrate Tachykinins - the classical C-terminal pentapeptide sequence: Phe-X-Gly-Leu-Met-NH2/Phe-Tyr-Pro-Gly-Met-NH2 / Phe-Tyr-Pro-Val-Met-NH2; and 2)

• physalaemin
• scyliorhinins I and II
• hylambatin C-terminal pentapeptide sequence Phe-Tyr-Gly-Met-Met-NH2.
• NKA
• NKB
• γ-neuropeptides
• NKA-like C-terminal decapeptides

--Mammalian Tachykinins

--- two preprotachykinin genes: the PPT-A gene, which encodes the sequences of SP, NKA, and neuropeptide K and neuropeptide-γ, and the PPT-B gene, which encodes the sequence of NKB, mRNA fordelingen er species specific, six groups of proteolytic enzymes called convertases, neuropeptider er “slow transmitters”, concept of co-release

• SP, 11as
• NKA (neuromedin L, neurokinin, and substance k) 9as, plus two elongated forms, neuropeptide K , 42as, and neuropeptide-γ, 19as
• NKB (neurokinin and neuromedin k) 10as

-

Tachykinin peptides are one of the largest families of neuropeptides, found from amphibians to mammals. They were so named due to their ability rapidly to induce contraction of gut tissue.[2] Tachykinins[3][4][5] excite neurons, evoke behavioral responses, are potent vasodilators, and contract (directly or indirectly) many smooth muscles.

The tachykinin family is characterized by a common C-terminal sequence, Phe-X-Gly-Leu-Met-NH2, where X is either an Aromatic or an Aliphatic amino acid. The genes that produce tachykinins encode precursor proteins called preprotachykinins, which are chopped apart into smaller peptides by posttranslational proteolytic processing. The genes also code for multiple splice forms that are made up of different sets of peptides.

Tachykinins are from ten to twelve residues long.

The two human tachykinin genes are called TAC1 and TAC3 for historical reasons, and are equivalent to Tac1 and Tac2 of the mouse, respectively. TAC1 encodes

neurokinin A (formerly known as substance K),

neuropeptide K (which has also been called neurokinin K[6]),

neuropeptide gamma, and

substance P.[7] The most notable tachykinin is Substance P.

Alpha, beta, and gamma splice forms are produced; the alpha form lacks exon 6 and the gamma form lacks exon 4. All three splice forms of TAC1 produce substance P, but only the beta and gamma forms produce the other three peptides. Neuropeptide K and neuropeptide gamma are N-terminally longer versions of neurokinin A that appear to be final peptide products in some tissues.[2]

TAC3 encodes

neurokinin B.[8]

Receptorer: Tre: NK1, NK2 and NK3 selectively bind to substance P, neurokinin A, and neurokinin B, respectively. GPCR

NEUROTRANSMITTERS

Neurotransmitters also known as chemical messengers, are endogenous chemicals that enable neurotransmission. They transmit signals across a chemical synapse, such as a neuromuscular junction, from one neuron (nerve cell) to another "target" neuron, muscle cell, or gland cell.[1] Neurotransmitters are released from synaptic vesicles in synapses into the synaptic cleft, where they are received by receptors on the target cells. Many neurotransmitters are synthesized from simple and plentiful precursors such as amino acids, which are readily available from the diet and only require a small number of biosynthetic steps to convert them. Neurotransmitters play a major role in shaping everyday life and functions. Their exact numbers are unknown but more than 100 chemical messengers have been identified.[2]

Mechanism

Neurotransmitters are stored in a synapse in synaptic vesicles, clustered beneath the membrane in the axon terminal located at the presynaptic side of the synapse. Neurotransmitters are released into and diffused across the synaptic cleft, where they bind to specific receptors in the membrane on the postsynaptic side of the synapse.[3]

Most neurotransmitters are about the size of a single amino acid, however, some neurotransmitters may be the size of larger proteins or peptides. A released neurotransmitter is typically available in the synaptic cleft for a short time before it is metabolized by enzymes, pulled back into the presynaptic neuron through reuptake, or bound to a postsynaptic receptor. Nevertheless, short-term exposure of the receptor to a neurotransmitter is typically sufficient for causing a postsynaptic response by way of synaptic transmission.

In response to a threshold action potential or graded electrical potential, a neurotransmitter is released at the presynaptic terminal. Low level "baseline" release also occurs without electrical stimulation. The released neurotransmitter may then move across the synapse to be detected by and bind with receptors in the postsynaptic neuron. Binding of neurotransmitters may influence the postsynaptic neuron in either an inhibitory or excitatory way. This neuron may be connected to many more neurons, and if the total of excitatory influences are greater than those of inhibitory influences, the neuron will also "fire". Ultimately it will create a new action potential at its axon hillock to release neurotransmitters and pass on the information to yet another neighboring neuron.[4]

daW:

Neurotransmittere kaldes også signalstoffer og er kemiske stoffer som frigøres i synapser og overfører signalet fra en neuron til en anden neuron, en muskelcelle eller en kirtelcelle via for eksempel en receptor. • Neurotransmittere

                       Aminosyrer
                                         Glutamat (hjernens kvantitativt vigtigste)
                                         Glycin
                                         GABA

                       Aminer
                                         Dopamin
                                         Noradrenalin
                                         Serotonin

                       Småmolekylære signalstoffer
                                         Acetylkolin
                                         ATP (AdenosinTriPhosphat)

                       Neuroaktive peptider

                       Peptidkæder på 5-30 aminosyrer

SECRETIN FAMILY

Glucagon/GIP/secretin/VIP hormones are a family of evolutionarily related peptide hormones that regulate activity of G-protein coupled receptors from secretin receptor family. A number of polypeptidic hormones, mainly expressed in the intestine or the pancreas, belong to a group of these structurally related peptides.[1][2]

One such hormone, glucagon, is widely distributed and produced in the alpha-cells of pancreatic islets.[3] It affects glucose metabolism in the liver[4] by inhibiting glycogen synthesis, stimulating glycogenolysis and enchancing gluconeogenesis. It also increases mobilisation of glucose, free fatty acids and ketone bodies, which are metabolites produced in excess in diabetes mellitus. Glucagon is produced, like other peptide hormones, as part of a larger precursor (preproglucagon), which is cleaved to produce

glucagon,

glucagon-like protein I,

glucagon-like protein II, and

glicentin.[5]

The structure of glucagon itself is fully conserved in all mammalian species in which it has been studied.[3]

Other members of the structurally similar group include

secretin,

gastric inhibitory peptide,

vasoactive intestinal peptide (VIP),

prealbumin,

peptide HI-27 and

growth hormone releasing factor.

Human hormones from this family

ADCYAP1;

GCG;

GHRH;

GIP;

SCT;

VIP;

OPIOID PEPTIDES

Opioid peptides are short sequences of amino acids that bind to opioid receptors in the brain; opiates and opioids mimic the effect of these peptides. Such peptides may be produced by the body itself, for example endorphins. The effects of these peptides vary, but they all resemble those of opiates. Brain opioid peptide systems are known to play an important role in motivation, emotion, attachment behaviour, the response to stress and pain, and the control of food intake. Opioid-like peptides may also be absorbed from partially digested food (casomorphins, exorphins, and rubiscolins). The opioid food peptides have lengths of typically 4-8 amino acids. The body's own opioids are generally much longer.

Opioid peptides are released by post-translational proteolytic cleavage of precursor proteins. The precursors consist of the following components: a signal sequence that precedes a conserved region of about 50 residues; a variable-length region; and the sequence of the neuropeptides themselves. Sequence analysis reveals that the conserved N-terminal region of the precursors contains 6 cysteines, which are probably involved in disulfide bond formation. It is speculated that this region might be important for neuropeptide processing.[1]

Opioid peptides produced by the body

The human genome contains several homologous genes that are known to code for endogenous opioid peptides. • The nucleotide sequence of the human gene for proopiomelanocortin (POMC) was characterized in 1980.[2] The POMC gene codes for endogenous opioids such as β-endorphin and gamma-endorphin.[3] The peptides with opioid activity that are derived from proopiomelanocortin comprise the class of endogenous opioid peptides called "endorphins". • The human gene for the enkephalins was isolated and its sequence described in 1982.[4] • The human gene for dynorphins (originally called the "Enkephalin B" gene because of sequence similarity to the enkephalin gene) was isolated and its sequence described in 1983.[5] • The PNOC gene encoding prepronociceptin, which is cleaved into nociceptin and potentially two additional neuropeptides.[1] • Adrenorphin, amidorphin, and leumorphin were discovered in the 1980s. • The endomorphins were discovered in the 1990s. • Opiorphin and spinorphin, enkephalinase inhibitors (i.e., prevent the metabolism of enkephalins). • Hemorphins, hemoglobin-derived opioid peptides, including hemorphin-4, valorphin, and spinorphin, among others. •

Opioid food peptides • Casomorphin (from casein found in milk of mammals, including cows) • Gluten exorphin (from gluten found in wheat, rye, barley) • Gliadorphin/gluteomorphin (from gluten found in wheat, rye, barley) • Soymorphin-5 (from soybean) • Rubiscolin (from spinach)

Amphibian opioid peptides[edit source | edit] • Deltorphin I and II • Dermorphin

Synthetic opioid peptides[edit source | edit]

Zyklophin – semisynthetic KOR antagonist derived from dynorphin A

ENDORPHIN

"a morphine-like substance originating from within the body".[1] The class of endorphin compounds includes α-endorphin, β-endorphin, γ-endorphin, α-neo-endorphin, and β-neo-endorphin. The principal function of endorphins is to inhibit the transmission of pain signals; they may also produce a feeling of euphoria very similar to that produced by other opioids.[2]

daW:

Endorfiner er primært smertedæmpende peptider, med morfinagtig virkning, der blandt andet udløses i hjernen. Der findes også syntetiske endorfiner, bl.a. i chokolade. Endorfin produceres, ud over ved smerter, f.eks. ved hård træning, hårdt arbejde, succes, forelskelse, sex eller latter, og kan foruden den smertestillende effekt også give en følelse af lyst, succes og energi. Endorfin er kraftigere end morfin, og man bliver afhængig af det.

Kemisk er endorfiner peptider.

Eksempler på naturlige endorfiner: • Enkefalin • Dynorfin • Neoendorfin

Endorfin

PRO-OPIOMELANOCORTIN

Pro-opiomelanocortin (POMC) is a precursor polypeptide with 241 amino acid residues. POMC is synthesized from the 285-amino-acid-long polypeptide precursor pre-pro-opiomelanocortin (pre-POMC), by the removal of a 44-amino-acid-long signal peptide sequence during translation. … precursor spaltes til flere forskellige peptide… receptor 5 typer GPCR, MC1R, MC2R for ACTH, MC3R, MC4R obesity!, MC5R

Function

POMC is cleaved to give rise to multiple peptide hormones. Each of these peptides is packaged in large dense-core vesicles that are released from the cells by exocytosis in response to appropriate stimulation:

• α-MSH produced by neurons in the arcuate nucleus has important roles in the regulation of appetite and sexual behavior, while α-MSH secreted from the intermediate lobe of the pituitary regulates the production of melanin. enW: The melanocyte-stimulating hormones, known collectively as MSH, also known as melanotropins or intermedins, are a family of peptide hormones and neuropeptides consisting of α-melanocyte-stimulating hormone (α-MSH), β-melanocyte-stimulating hormone (β-MSH), and γ-melanocyte-stimulating hormone (γ-MSH) that are produced by cells in the intermediate lobe of the pituitary gland…. An increase in MSH will cause darker skin in humans too. MSH increases in humans during pregnancy. This, along with increased estrogens, causes increased pigmentation in pregnant women. Cushing's syndrome due to excess adrenocorticotropic hormone (ACTH) may also result in hyperpigmentation, such as acanthosis nigricans in the axilla. Most people with primary Addison's disease have darkening (hyperpigmentation) of the skin, including areas not exposed to the sun; characteristic sites are skin creases (e.g. of the hands), nipple, and the inside of the cheek (buccal mucosa), new scars become hyperpigmented, whereas older ones do not darken. This occurs because MSH and ACTH share the same precursor molecule, proopiomelanocortin (POMC).Different levels of MSH are not the major cause of racial variation in skin colour. However, in many red-headed people, and other people who do not tan well, there are variations in their hormone receptors, causing them to not respond to MSH in the blood.

• ACTH is a peptide hormone that regulates the secretion of glucocorticoids from the adrenal cortex. enW: Adrenocorticotropic hormone (ACTH), also known as corticotropin (INN, BAN) (brand names Acortan, ACTH, Acthar, Acton, Cortigel, Trofocortina),[1][2] is a polypeptide tropic hormone produced and secreted by the anterior pituitary gland.[3] It is an important component of the hypothalamic-pituitary-adrenal axis and is often produced in response to biological stress (along with its precursor corticotropin-releasing hormone from the hypothalamus). Its principal effects are increased production and release of cortisol by the cortex of the adrenal gland. Primary adrenal insufficiency, also called Addison's disease, occurs when adrenal gland production of cortisol is chronically deficient, resulting in chronically elevated ACTH levels; when a pituitary tumor is the cause of elevated ACTH (from the anterior pituitary) this is known as Cushing's disease and the constellation of signs and symptoms of the excess cortisol (hypercortisolism) is known as Cushing's syndrome. Conversely, deficiency of ACTH is a cause of secondary adrenal insufficiency, often as a result of hypopituitarism. ACTH is also related to the circadian rhythm in many organisms.[4]In addition to its endogenous role, ACTH is used clinically as a diagnostic agent in assessing adrenal function.[1][2][3] … POMC, ACTH and β-lipotropin are secreted from corticotropes in the anterior lobe (or adenohypophysis) of the pituitary gland in response to the hormone corticotropin-releasing hormone (CRH) released by the hypothalamus.[5] ACTH is synthesized from pre-pro-opiomelanocortin (pre-POMC). The removal of the signal peptide during translation produces the 241-amino acid polypeptide POMC, which undergoes a series of post-translational modifications such as phosphorylation and glycosylation before it is proteolytically cleaved by endopeptidases to yield various polypeptide fragments with varying physiological activity. These fragments include:[6]

• β-Endorphin and [Met]enkephalin are endogenous opioid peptides with widespread actions in the brain. … 31 aa (alpha- Endorphin er de første 16 aa).

Se også http://thebrain.mcgill.ca/flash/a/a_03/a_03_m/a_03_m_dou/a_03_m_dou.html

Peptider

Bacteriociner er peptid-toxiner produceret af bakterier for at hæmme væksten af andre bakterier.

Mælkepeptider forekommer naturligt i mælkeprodukter som led i enzymatisk nedbrydning.

CYTOKINER

Automatoversættelse: Cytokiner (cyto, fra græsk "κύτταρο" kyttaro "celle" + kines, fra græsk "κίνηση" kinisi "bevægelse") er en bred og løs kategori af små proteiner (~5-20 kDa), der er vigtige ved cellesignalering. De er frigivet fra celler for at påvirke andre celler. Cytokiner kan også være involveret i autokrin signalering. 

Cytokiner omfatter kemokiner, interferoner, interleukiner, lymphokines samt tumornekrosefaktorer, men generelt ikke hormoner eller vækstfaktorer (på trods af overlap i terminologien). Cytokiner produceres af en lang række celler: immunceller som makrofager, B-lymfocytter, T-lymfocytter og mast celler samt endothelceller, fibroblaster, og forskellige stromale celler; en given cytokin kan være produceret ved hjælp af mere end én type celle.

Signalstoffer, Immunomodulerende stoffer

small proteins (~5–20 kDa) that are important in cell signaling. They are released by cells and affect the behavior of (other) cells. produced by a broad range of cells, including immune cells like macrophages, B lymphocytes, T lymphocytes and mast cells, as well as endothelial cells, fibroblasts, and various stromal cells

Ordbog:

Autocrine = virker på samme celle

Paracrine = virker på naboceller

Endocrine = systemisk virkning

Cytokine receptor [http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4445396/figure/F1/

Insights into cytokine-receptor interactions from cytokine engineering. 2015], structural and functional conservation = glycoproteiner, 2-4 receptor chains,

Identisk kæde: Hematopoietic superfamily (Type I): gp130 family, γc family, and βcfamily + GH-R.

IFN superfamilie (Type II)

Type I cytokine receptors, hemopoietin receptors med WSXWS-motiv

Type II cytokine receptors are heterodimers or multimers associated with a tyrosine kinase belonging to the Janus kinase (JAK) family.

Chemokines (tidligere andre navne) - induce chemotaxis, tiltrækker leucocytter 8-10 kDa, ens struktur m 4 cys, four main subfamilies : CXC, CC, CX3C and XC.

Chemokine receptors, G protein-linked transmembrane receptors

Interferonser, INF er en gruppe signalproteiner, der dannes som respons på tilstedeværelsen af patogener (virus, bakterier og parasiter) og tumorceller, aktiverer immunsystemet

Mere end 20 forskellige proteiner, tre typer, glycoprotein 20.000-25.000 Da

Interferon receptor superfamilie. To kæder. Binding and activation of the receptor stimulates Janus protein kinases, which in turn phosphorylate several proteins, including STAT1 and STAT2.

interleukins,

36 kendte interleukiner

IL-2 glycoprotein

IL-6 26 kDa

lymphokines,

Monokiner

Colony stimulating factors

tumour necrosis factor

Se HORMONER OG VÆKSTFAKTORER