Peptides

<p>Melittin is a 26-residue peptide originally isolated from venom of the European honeybee. Melittin is a cationic, hemolytic peptide from honey bee venom. Melittin lowers the surface tension at the plasma membrane and causes cell lysis. Melittin exhibits potent anti-inflammatory and antimicrobial activity. Melittin has been extensively used as a model peptide for observing membrane lipid-protein interactions.</p>

<p>TAT (48-60) amide is a cell penetrating cationic peptide derived from the N-terminus of the Tat protein, which is a trans-activator of the transcription protein present in the human immunodeficiency virus (HIV). The 48-60 region of the TAT peptide is an arginine-rich bascic domain which as a whole has three domains that function to aid HIV through transactivation, DNA binding and nuclear transport. As a cell penetrating peptide (CPP) TAT aids in the cellular uptake of molecules and hence serves a valuable purpose in transduction methods. This property has been demonstrated through its ability of allowing toxins such as the neurotoxin Botulinum neurotoxin Type A, produced by the Clostridium botulinum type A bacteria to penetrate the skin barrier non-invasively.This peptide has an uncharged C-terminal amide.</p>

<p>β-Amyloid 1-10 (Aβ1-10) is one of many short Aβ species found in vivo and is formed by the cleavage of amyloid β precursor protein by β- and α-secretase.-Amyloid β-protein (Aβ) has been identified as the key subunit of the extracellular plaques found in the brains of patients with Alzheimer disease (AD) and Down syndrome (DS). Aβ has therefore been extensively studied as a potential target for treatment of AD.Aβ is formed from the cleavage of the large, transmembrane protein- APP (amyloid precursor protein). Cleavage of APP by β- and then α-secretases results in the formation of Aβ. Aβ can aggregate to produce amyloid-β oligomers, which are thought to be highly neurotoxic. Over time Aβ can further aggregate to produce the characteristic senile plaques present in AD and DS. Aβ can be degraded by enzymes such as neprilysin, insulin degrading enzyme or endothelin converting enzyme. At physiological levels Aβ may be involved in controlling synaptic activity and neuronal survival. Biotin is C-terminally linked to the peptide via ethylenediamine-for convenient detection and purification. Alternative β-Amyloid fragments and labels are also available, please refer to our peptide catalogue for availability.</p>

<p>The SARS-CoV-2 non-structural protein 13 (NSP13) has been identified as a target for anti-viral therapeutics due to its highly conserved sequence and is essential for viral replication.  NSP13 is part of the helicase superfamily 1B. As an NTPase and RNA helicase, NSP13 binds to RNA-dependent RNA polymerase and acts in concert with the replication-transcription complex to stimulate backtracking and further activate NSP13 helicase activity. These factors make NSP13 a good target for developing new antiviral drugs. In addition, the identification of epitopes within the NSP13 sequence can help design more effective SARS-CoV-2 vaccines.Models have predicted epitopes exhibiting antigenicity, stability and interactions with MHC class-I and class-II molecules. NSP13 (321-335) is an epitope candidate with various HLA restrictions. This epitope can be used to better vaccine design for more durable CD4+ and CD8+ T cell responses for long-lasting immunity.</p>

<p>Annexin A1 (2-12) is derived from the Annexin A1 protein which is a member of the Ca2+ dependent phospholipid binding protein family of Annexins A1 to A13. Structurally Annexin is comprised of a C-terminal core region and an N-terminal region. Calcium binding sites featured in the core region allow Annexin A1 to bind to cell membranes to induce membrane aggregation in a calcium dependent manner. Furthermore Annexin A1's N-terminal region performs extracellular signalling through forming complexes with SH2 domain containing proteins. Different lengths of the Annexin family's N-terminus contributes to how the Annexins effect key processes such as cell proliferation, apoptosis, growth and differentiation.Annexin A1 can be categorised as being both anti-inflammatory and pro-inflammatory. One example of how Annexin A1 demonstrates anti-inflammatory properties is through activating the formyl peptide receptor family's (FGRs) downstream cascade. Consequently the extracellular regulated kinase (ERK) and mitogen-activated protein kinase (MAPK) are phosphorylated, causing subsequent transcription factors involved in the regulation of T cells to generate anti-inflammatory effects. Another is through inhibiting phospholipase A2 which prevents the release of inflammatory factors and the formation of arachidonic acid precursors. This property has contributed to inflammation studies such as where the inhibition of pro-inflammatory prostaglandins by Annexin A1 was used to investigate leukocyte aggregation.During its anti-inflammatory role Annexin A1 uses the active peptide Ac2-26 located on its N-terminus. It is evident Annexin A1 can be labelled as being pro-inflammatory due to it inducing pro-inflammatory cytokines, following its phosphorylation by PKC. This results in its translocation into the nucleus of BV-2 microglial cells.</p>

<p>Galanin (1-30) (human) is an endogenous neuropeptide with endocrine, metabolic and behavioural effects. Galanin has a role in intestinal smooth muscle contraction, insulin and somatostatin release, and synaptic neurotransmission.Galanin is widely distributed in the central nervous, peripheral, and endocrine systems. Galanin's overarching function is as an inhibitory, hyper-polarizing neuromodulator for classical neurotransmitters like acetylcholine and serotonin. Galanin interacts with 3 receptor subtypes, GalR1-3 which are G protein-coupled receptors inserted into the plasma membrane. GalR1 is believed to activate a Gβγ pathway to regulate MAPK activation. GalR2 can also activate the MAPK pathway, but unlike GalR1, there is detectable inositol phosphate production. GalR3 is associated with the Galphai/o pathway. Activation of the receptor leads to a cellular influx of K+. Each receptor has been associated with neurological diseases such as GalR3 and epilepsy.Galanin protects against various physiological insults in vitro, including excitotoxicity and β-amyloid toxicity. Changes in galanin have been widely studied concerning Alzheimer's disease, and galaninergic neurons are spared in late-stage Alzheimer's relative to non-galaninergic neurones.Galanin (1-30) has been used as an agonist for the GalR2 receptor in vitro for calcium mobilisation assays to understand the role Galanin/GalR2 play in multiple sclerosis.Galanin (1-30) is provided with an N-terminal 5-FAM, a widely used green fluorescent reagent ideal for peptide labelling and detection. The excitation/emission for this reagent is 490 nm/520 nm.</p>

<p>The SARS-CoV-2 spike protein is present on the outside of the virus particles and can bind to angiotensin-converting enzyme II (ACE2) present on the host cells. The C-terminal receptor binding domain (RBD) of the spike protein binds to the N-terminal peptidase M2 domain of ACE2. This receptor binding results in the internalisation of the virus-receptor complex and is, therefore the mechanism of entry of SARS-CoV-2 into host cells.The spike protein residues NLNESLIDL (1192-1200) from SARS-CoV-2 have been identified as a T-cell epitope with a predicted HLA restriction. Immune targeting of confirmed epitopes may potentially offer protection against SARS-CoV-2 and help the development of vaccines for long-lasting immunity.</p>

<p>PFR-[AMC]</p>

<p>Galanin is a neuropeptide synthesised and released by the brainstem locus coeruleus (LC). Galanin is expressed in most LC neurons in rodents and humans. Galanin has been shown to inhibit LC activity by hyperpolarising LC neurons, suppressing their spontaneous firing rate, and enhancing alpha2-adrenergic receptor-mediated negative feedback. Galanin is also a potent trophic and neuroprotective factor throughout the nervous system.Galanin is widely distributed in the central nervous, peripheral, and endocrine systems. Galanin's overarching function is as an inhibitory, hyper-polarizing neuromodulator for classical neurotransmitters like acetylcholine and serotonin. Galanin interacts with 3 receptor subtypes, GalR1-3 G protein-coupled receptors inserted into the plasma membrane. GalR1 is believed to activate a Gβγ pathway to regulate MAPK activation. GalR2 can also activate the MAPK pathway, but unlike GalR1, there is detectable inositol phosphate production. GalR3 is associated with the Galphai/o pathway. Activation of the receptor leads to a cellular influx of K+. Each receptor has been associated with neurological diseases such as GalR3 and epilepsy.Galanin protects against various physiological insults in vitro, including excitotoxicity and β-amyloid toxicity. Changes in galanin have been widely studied concerning Alzheimer's disease, and galaninergic neurons are spared in late-stage Alzheimer's relative to non-galaninergic neurones.Galanin is provided here with an N-terminal 5-TAMRA, a widely used red fluorescent reagent ideal for peptide labelling and detection. The excitation/emission for this reagent is 555 nm/580 nm. Cymit Quimica Laboratories Ltd is a custom peptide provider. If you desire an alternate dye, please contact us to request a custom synthesis.</p>

<p>Isotocin is a nonapeptide of the arginine vasopressin-oxytocin family produced exclusively in the preoptic area (POA) of teleosts. As a homologue of mammalian oxytocin, studying fish nonapeptides has shown that Isotocin mediates social and reproductive behaviour in fishes. Functional isotocin is stored in granules at the axon terminal with a carrier peptide, neurophysin. Stimuli leads to isotocin dissociation, to be released into the bloodstream or to cross over into the brain. It binds to G-protein coupled receptors (GPCRs), which subtype isotocin binds to defines the following physiological action. It, like other nonapeptides, is a neuromodulator in the CNS, but when distributed by the bloodstream, it acts as a peripheral hormone, such as regulating osmoregulation. Isotocin levels are sex-dependent and linked to the reproductive cycle.HPLC is a sensitive method to detect bioavailable isotocin and other nonapeptides. Measurement of mRNA levels of isotocin has been important to demonstrate the cyclical changes to regulate the endocrine calendar and diurnal rhythm. The level of isotocin is also considered a biomarker for aggression in behavioural indicators of fish welfare studies.</p>

<p>Alyerserin-2c is a C-terminally α-amidated 17 residue cationic anti-microbial peptide (AMP). Anti-microbial peptides (AMPs) are produced by the innate immune system and are expressed when the host is challenged by a pathogen. The Alyerserin family of peptides was first identified in norepinephrine-stimulated skin secretions of the midwife toad-Alytes obstetricans-(Alytidae). Alyteserin-2a, 2b and -2c show some sequence identity with bombinin H6, a peptide from the skins Bombinatoridae family of frogs.Alyteserin-2c is most potent against the Gram-positive bacteria-Staphylococcus aureus and has weak haemolytic activity against human erythrocytes.Alyteserin contain at least 50% hydrophobic amino acids. Hydrophobic residues contribute to the insertion of the peptide into the hydrophobic membrane core which results in membrane disruption and death of the pathogen. Due to their mechanism of action it is thought to be less likely for resistance to develop towards these peptides compared to conventional antibiotics.</p>

<p>Galanin is a neuropeptide synthesised and released by the brainstem locus coeruleus (LC). Galanin is expressed in most LC neurons in rodents and humans. Galanin has been shown to inhibit LC activity by hyperpolarising LC neurons, suppressing their spontaneous firing rate, and enhancing alpha2-adrenergic receptor-mediated negative feedback. Galanin is also a potent trophic and neuroprotective factor throughout the nervous system.Galanin is widely distributed in the central nervous, peripheral, and endocrine systems. Galanin's overarching function is as an inhibitory, hyper-polarizing neuromodulator for classical neurotransmitters like acetylcholine and serotonin. Galanin interacts with 3 receptor subtypes, GalR1-3, these G protein-coupled receptors are inserted into the plasma membrane. GalR1 is believed to activate a Gβγ pathway to regulate MAPK activation. GalR2 can also activate the MAPK pathway, but unlike GalR1, there is detectable inositol phosphate production. GalR3 is associated with the Galphai/o pathway. Activation of the receptor leads to a cellular influx of K+. Each receptor has been associated with neurological diseases such as GalR3 with epilepsy.N-terminal fragments naturally occur in vivo, but their relevance is unclear. Some N-terminal fragments reduce metabolic and functional disorders in experimental heart damage. Using N-terminal fragments such as galanin (3-13) can clarify the function of full-length galanin during myocardial ischemia and reperfusion injury. This may highlight new agonists/antagonists for the galanin GalR receptors that can be putative therapeutic targets.</p>

<p>Protease activated receptors (PARs) are a distinctive four-member family of seven transmembrane G protein-coupled receptors (GPCRs) widely expressed in inflammatory cells. PARs are cleaved by certain serine proteases to expose a tethered ligand domain, this ligand domain then binds to and activates the receptors to initiate multiple signalling cascades. These PAR-activating proteases therefore represent PAR agonists. This PAR-4 agonist peptide represents the N-terminal sequence of the 'tethered ligand' and is therefore capable of activating the receptor independently of N-terminal proteolysis.</p>

<p>The SARS-CoV-2 spike protein is present on the outside of the virus particles and can bind to angiotensin-converting enzyme II (ACE2) present on the host cells. The C-terminal receptor binding domain (RBD) of the spike protein binds to the N-terminal peptidase M2 domain of ACE2. This receptor binding results in the internalisation of the virus-receptor complex and is, therefore the mechanism of entry of SARS-CoV-2 into host cells.The spike protein residues SVLNDILSR (975-983) from SARS-CoV-2 have been identified as a T-cell epitope with a predicted HLA restriction. Immune targeting of confirmed epitopes may potentially offer protection against SARS-CoV-2 and help the development of vaccines for long-lasting immunity.</p>

<p>Portion of EBV</p>

<p>Maier8 is a short basic amphipathic peptide that functions as a cell-penetrating peptide (CPP). Maier8 has been studied in comparison to other CPPs and found to be highly efficient at crossing into the cell without causing cytotoxicity. Furthermore, Maier8 has a long half-life which is vital for effective delivery of the conjugate.Maier8 is labelled at the N-terminus with an alkyne attachment for ease of reaction with an opposite Click reactive partner (azide). Azide-alkyne cycloaddition has become the most popular Click reaction. Alkyne-Maier8 allows a wide variety of applications, particularly for conjugation, modification, and drug delivery.</p>

<p>Temporin-SHf is a broad spectrum anti-microbial peptide (AMP) with activity against Gram-positive and Gram-negative bacteria and yeasts, which displays no haemolytic activity. Temporin-SHf was first isolated from the skin of the frog Pelophylax saharica and is a member of the temporin family of AMPs. Temporins are a large family of short, linear, AMPs produced in the skin of frogs belonging to Rana species, but are also found in wasp venom. Temporin-SHf is the smallest natural linear AMP found to date and has a highly hydrophobic sequence (75%) plus the highest percentage of phenylalanine residues of any known peptide (50%).Temporin-SHf works by disrupting the acyl chain packing of anionic lipid bilayers, causing cracks and microbial membrane disintegration through a detergent-like effect. Temporin-SHf is a promising candidate for the development of a new class of anti-microbial drugs.</p>

<p>Human Lysozyme (107-115) is derived from human lysozyme, a glycosidase enzyme which can kill both gram-positive and gram-negative bacteria. This can be carried out in a catalytic manner through the hydrolysis of peptidoglycan in the cell wall or alternatively in a non-catalytic manner. Due to the surface of bacteria being negatively charged, they are vulnerable to be targeted by the human lysozyme which is cationic. These antimicrobial properties can be used therapeutically as an anti-pseudomonal agent.Structurally the human lysozyme is comprised of four intramolecular disulphide bonds, four alpha helices within an alpha domain and β-sheets within a β-domain. Human lysozyme (107-115) is found within the α-domain.</p>

<p>Broad-spectrum antibacterial, active against multidrug-resistant Gram-negative bacteria. Acts though permeabilizing the bacterial membrane and also shows anti-inflammatory activity via a TLR4-mediated NF-KB signaling pathway. Significantly improves survival in a mouse sepsis model.</p>

<p>This anti-microbial peptide (AMP) has been shown to cause lysis of several human cancer cell lines. Macropin-2 is most potent against CCRF-CEM T lymphoblastoid (human acute lymphoblastic leukemia) cells. At higher concentrations Macropin-2 also causes lysis of human umbilical vein endothelial cells (HUVEC), rat intestinal epithelial cells (IEC), human cervix carcinoma (HeLa) cells and human colon adenocarcinoma (SW480). Macropin-1 is also available in our catalogue.</p>

<p>The Bid BH3 Peptide is derived from the pro-apoptotic proteins Bid (BH3-interacting domain death agonist) and BH3, which are both members of the BCL-2 family proteins and activate the BAX and BAK proteins to promote apoptosis.The process of apoptosis can be activated by the intrinsic or extrinsic pathways, the former is activated by stress stimuli such as DNA damage and nutrient deficiency, while the latter is induced through activation of the death receptors FAS and TRAIL.The BCL-2 family's transmembrane anchor at the C-terminus allows them to locate at the mitochondrial outer membrane and play a vital role in apoptosis.Within the mitochondria BH3 molecules, containing the members BID, BIM, PUMA and NOXA, can be activated by the intrinsic pathway. These in turn can initiate the homo-oligomerisation of BAX and BAK which induce mitochondrial outer membrane permeabilisation (MOMP) and the release of cytochrome c into the cytosol. Here cytochrome c associates with APAF-1 and dATP, ultimately activating effector caspase3/7 and apoptosis.In addition to Bid's role in apoptosis, it also plays a role within a mitosis checkpoint and genomic stability maintenance. Bid's main role is in the extrinsic pathway of apoptosis. When the death receptors are activated Caspase-8 generates tBid through the cleavage of Bid. This then locates to and targets Bax to the outer mitochondrial membrane (OMM) where it induces permeabilisation and hence apoptosis.</p>

<p>Acetylated α-synuclein (1-13) is derived from the alpha-synuclein intrinsically disordered protein which is found in the neurons and presynaptic terminals. Encoded by the SNCA1/PARK1 gene alpha-synclein is structurally composed of 140 amino acids, making up the three domains: N-terminal membrane binding domain, a hydrophobic non-amyloid-β component domain and a hydrophilic C-terminal domain. Usually alpha-synuclein plays a role in protecting neurons from apoptotic stimuli and is involved in synaptic vesical trafficking.However it has been found that the accumulation of alpha-synuclein aggregates can lead to neurodegenerative diseases such as Parkinson disease, dementia with Lewy bodies and multiple system atrophy. It is further involved in the fibrilisation of amyloid-b and tau which play a major role in Alzheimer disease. Amyloid fibrils are formed from alpha synuclein monomers within the cytosol and when bound to membranes these monomers can undergo conformational changes to form protofibrils and then ring like oligomers. This can result in the formation of transmembrane pores which disrupts the membrane, calcium homeostasis and signalling.Alpha-synuclein can be subjected to the post-translational modifications of phosphorylation and N-terminal acetylation. When acetylation occurs at the N-terminus of an alpha-synuclein monomer, the intramolecular hydrogen bonds are altered thus reducing the rate of alpha-synuclein aggregation and the strength at which it interacts with the membrane is increased.</p>

<p>LRRK2 is a leucine rich repeat kinase 2. Increase in LRRK2 kinase activity due to mutation has been linked to numerous forms of Parkinson disease (PD). Theoretically, identification of suitable inhibitors of LRRK2 could be the basis for treatments of PD. Markers of LRRK2 activity and function are available that may be clinically relevant in the future as prognostic indicators. Nictide is a substrate model peptide for LRRK2 activity in in vitro kinase assay analysis. -LRRK2 phosphorylates Rab GTPases and alters their association with effector proteins leading to changes in a vast array of cellular functions including the immune response. The use of in vitro kinase assays with small molecules substrates makes screening for LRRK2 inhibitors possible. Alongside nictide, LRRKtide is also used in the same in vitro assays as a substrate model peptide for LRRK2.- Nictide and LRRKtide are available in our catalogue.</p>

<p>P1A was the first tumour antigen identified to be recognised by cytotoxic T cells. Tumour antigens are highly expressed on tumour cells however, they are also expressed during early embryogenesis then largely silenced in adulthood thus termed onco-fetal antigens. Targetting tumours expressing these antigens is possible due to their absence in adult tissue (apart from within the testes and placenta). The immune response to the P1A antigen is the major component of the tumour rejection response observed in normal mice. P1A antigen has been tested as a vaccine for tumours to induce P1A-specific CD8+ tumour-infiltrating lymphocytes (TILs). Therefore, the P1A antigen is a useful tool in the search in new cancer immunotherapies using targeted tumour-specific antigens.</p>

<p>Cell permeable peptide where the amyloid forming sequence is homologous to a nucleating sequence from the human Tau protein (306VQIVYK311). Forms long lived oligomers that are taken up by endocytosis and is cytotoxic in multiple cell lines.- Co-localizes with pathological hyperphosphorylated forms of Tau in vitro.</p>

<p>Alpha-synuclein (1-13) is derived from the alpha-synuclein intrinsically disordered protein which is found in the neurons and presynaptic terminals. Encoded by the SNCA1/PARK1 gene alpha-synclein is structurally composed of 140 amino acids, making up the three domains: N-terminal membrane binding domain, a hydrophobic non-amyloid-β component domain and a hydrophilic C-terminal domain. Usually alpha-synuclein plays a role in protecting neurons from apoptotic stimuli and is involved in synaptic vesical trafficking.Accumulation of alpha-synuclein aggregates can lead to neurodegenerative diseases such as Parkinson disease, dementia with Lewy bodies and multiple system atrophy. It is further involved in the fibrilisation of amyloid-b and tau which play a major role in Alzheimer disease. Amyloid fibrils are formed from alpha synuclein monomers within the cytosol and when bound to membranes these monomers can undergo conformational changes to form protofibrils and then ring like oligomers. This can result in the formation of transmembrane pores which disrupts the membrane, calcium homeostasis and signalling.In familial Parkinson disease the SNCA1 gene, can be subjected to point mutations such as A30P, E46K and A53T, or over expression. These can result in the increased aggregation of alpha-synuclein.The methionine at position 5 is oxidised and the oxidation of methionine is common in neurodegenerative diseases and promotes the accumulation of altered α-synuclein. Furthermore when these methionine residues are oxidised, methionine sulfoxides are produced.</p>

<p>The ccβ peptide has been used to study conformational changes in response to stimuli such as temperature and salt. The ccβ peptide adopts a three-stranded alpha-helical coiled-coil structure at low temperature and changes to an amyloid conformation with increasing temperature. The ccβ peptide can be used as a model for prion diseases and in amyloid studies.</p>

<p>PAR2 plays a particular role in protecting the gastric mucosa mediated by capsaicin-sensitive sensory neurons. PAR2 also serves to aid in gut smooth muscle motility- colon inflammation pathway- hyperalgesia and is also anti-inflammatory in other circumstances.Development of selective agonists for PAR2 are crucial for research. (2-Furoyl)-LIGRL-amide is a far more potent agonist than the native PAR2 activating peptide SLIGRL-NH2. In mice, oral administration conferred cytoprotection from gastrointestinal lesions. However, it was inhibited by capsaicin pre-treatment.</p>

<p>Glucagon-like peptide (GLP)-1 is a gastrointestinal peptide hormone with multiple roles in relation to metabolism. The primary role of GLP-1 is increasing insulin secretion in the presence of high plasma glucose levels, in addition, GLP-1 also suppresses glucagon secretion from the pancreas. GLP-1 slows down gastric emptying and regulates appetite, both valuable in reducing food intake and body weight. These roles of GLP-1 make it a useful target in the management of type 2 diabetes mellitus (T2DM).GLP-1 exerts its effects by binding to and activating the class B G protein-coupled receptor (GPCR): GLP-1 receptor (GLP-1R). Receptor activation in turn activates signalling pathways which culminates in insulin secretion via CAMP and Ca2+ signalling.Recently evidence has increased for GLP-1 playing a cardio-protective role as well as regulating immune responses and even in kidney function. GLP-1 may also exert neuroprotective and neurotropic effects as it can decrease endogenous levels of amyloid-β (Aβ) and prevent Aβ-induced cell death.This peptide contains an N-terminal Biotin tag for simple detection and purification.</p>

<p>C105Y is a cell penetrating peptide aiding in the delivery of DNA into cells.</p>

<p>This peptide is recognised and cleaved by the enzyme Sortase A (SrtA) from-Staphylococcus aureus. The catalytic cysteine residue in the active site of SrtA, serves as a nucleophile to cleave the peptide bond between threonine and glycine. Cleavage results in the formation of a thioacyl intermediate between the peptide and SrtA. This intermediate is then resolved by the N-terminus of an (oligo)glycine nucleophile, resulting in the creation of a new peptide bond that links the peptide and its-nucleophile, resulting in the creation of a new peptide bond that links the peptide and its fluorescent- to the incoming nucleophile.- This method of protein labelling is known as sortagging5-Carboxytetramethylrhodamine (5-TAMRA) is a widely used fluorescent dye which excites at 546 nm and emits at 579 nm</p>

<p>[Ala144]-PLP (139-151) is the Ala 144 form of Proteolipid protein (PLP), an epitope of immunodominant encephalitogenic PLP and is involved in promoting encephalomyelitis.</p>

<p>GRGD-acid is a cell adhesive peptide containing the RGD motif. This enables it the ability to increase cell adhesion and rates of cell growth, differentiation and proliferation. When immobilised onto a Poly(etheretherketone) (PEEK) surface it has been shown to increase cell adhesion and proliferation in MC3T3-E1 cells. GRGD could therefore be used in dental implants.</p>

<p>C-terminal fragment of adrenocorticotropic hormone (ACTH), also known as corticotropin, with a C-terminal cysteine residue for conjugation. ACTH (7-39) is a competitive antagonist of ACTH receptor (ACTHR), also known as melanocortin type 2 receptor (MC2R).ACTH is a member of the melanocortins-peptide family, this tropic hormone is produced and secreted by the anterior pituitary gland. ACTH is an important component of the hypothalamic-pituitary-adrenal (HPA) axis and is often produced in response to biological stress. ACTH acts to increase the production and release of cortisol via its interaction with ACTHR. Receptor activation increases the intracellular concentration of cAMP via adenylyl cyclase. -Abnormal ACTH levels in the body have been linked to primary adrenal insufficiency/Addison's disease, Cushing's disease and secondary adrenal insufficiency.</p>

<p>Angiotensin-IV is primarily produced from angiotensin-III by the removal of an arginine residue from the N-terminal by membrane alanyl aminopeptidase N (AP-N). Ang-IV can however also be formed by the action of aminopeptidases on Ang-I directly.Ang-IV has been shown to enhance cognitive functions, although how it does this in still unclear. It has been suggested that Ang-IV is able to inhibit the insulin-regulated aminopeptidase (IRAP) receptor in the brain (originally defined as the AT(4) receptor). IRAP is a single-spanning transmembrane zinc-metallopeptidase that belongs to the M1 family of aminopeptidases and its substrates include vasopressin, somatostatin, and cholecystokinin. The half-life of these compounds are prolonged when IRAP is inhibited by Ang-IV, and this may result in the enhanced cognitive abilities seen with Ang-IV treatment. c-Met, a tyrosine kinase receptor that binds hepatocyte growth factor (HGF) has also been proposed as an Ang IV targets. c-Met is associated with memory and learning consolidation.</p>

<p>C- terminal fragment of adrenocorticotropic hormone (ACTH) also known as corticotropin, and competitive antagonist of ACTH receptor (ACTHR), also known as melanocortin type 2 receptor (MC2R).ACTH is a member of the melanocortins-peptide family, this tropic hormone is produced and secreted by the anterior pituitary gland. ACTH is an important component of the hypothalamic-pituitary-adrenal (HPA) axis and is often produced in response to biological stress. ACTH acts to increase the production and release of cortisol via its interaction with ACTHR. Receptor activation increases the intracellular concentration of cAMP via adenylyl cyclase. Abnormal ACTH levels in the body have been linked to primary adrenal insufficiency/Addison's disease, Cushing's disease and secondary adrenal insufficiency.</p>

<p>Auto-inducing peptide (AIP) is a cyclic thiolactone quorum sensing peptide from Staphylococcus aureus which is responsible for activating the agr response. AIP is released from the bacteria and its extracellular concentration is then sensed by a two-component system on the bacterial surface, AgrC and AgrA. AgrC is the membrane histidine kinase receptor and AgrA is a response regulator- upon binding of AIP, AgrC phosphorylates AgrA.AIP accumulates during growth activating an AgrC and AgrA cascade when it reaches a critical signal level. This cascade activates P2 and P3 promoters which autoactivate the agr system and upregulate RNAIII transcription. RNAIII regulates the expression of virulence factors including toxins, super-antigens, and exo-enzymes. Extensive research to identify AIP:AgrC inhibitors aims to find therapeutics against pathogens.AgrD is the precursor peptide of AIP, and AgrB is an integral membrane endopeptidase essential to biosynthesize AIP. This AIP system is conserved among many Gram-positive bacteria. S. aureus strains are categorized into four groups (I-IV) according to their AIP signal and cognate extracellular receptor, AgrC.  AIP-I has the characteristic five-residue thiolactone ring with a short N-terminal extension. AIP-I has been used to generate a biosensor for the detection of S. aureus in nanomolar range for use in hospital settings.</p>

<p>Histone H3.2 is a highly common variant of the core histone H3 which is found in all eukaryotes except budding yeast. H3.2 is replication-dependent and is associated with gene silencing. Histone variants can replace canonical histones in certain cells or stages of development and help regulate numerous nuclear processes including transcription, DNA repair and chromosome segregation.Histone 3 (H3) which is one of the four core histones (H2A, H2B, H3 and H4) fundamental in compacting eukaryotic DNA into the nucleosome. Both H4 and H3 are highly conserved and perform roles in binding to segments of DNA which enter and leave the nucleosome and in chromatin formation. Similar to the other core histone, H3 has a globular domain and a flexible N-terminal domain, 'histone tail' which can undergo modifications such as acetylation, methylation, phosphorylation and ubiquitination.</p>

<p>TKD (450-463) is an immunogenic heat shock protein 70 peptide which has been labelled at the N-terminus with Cys(Npys).</p>

<p>The development of type I diabetes occurs when auto-aggressive T cells are not controlled by T regulatory cells and are allowed to destroy pancreatic islet cells. This ultimately eliminates the production of insulin within the body.  A more precise understanding of the regulatory T cell's antigen specificity by using antigens can provide significant clinical insights into the development of long-term diabetes. The proinsulin 90-104 fragment was used to test antigen-specific T-cell responses in type I diabetes CD4+ T cells. This peptide has helped show that the development of diabetes is linked to an increase in proinsulin-specific T regulatory cells, which may be regulating the rise in auto-aggressive T cells. Further work with the proinsulin 90-104 peptide could help design novel antigen-specific therapy.</p>

<p>Integral membrane protein TGN38 cycles via endosomes between the cell surface and the trans-Golgi network (TGN). Peptides conjugated to the TGN38 sequence inhibit vesicle budding from TGN membranes-in vitro.-This leads to the conclusion that TGN38 is crucial for forming constitutive exocytic vesicles. The trafficking motif SDYQRL in the cytoplasmic domain at the C-terminal contains a critical tyrosine residue (Y). The motif interacts with the medium-chain adaptor subunits of AP-1/2 to allow sorting from the TGN. Mutation of the key tyrosine dramatically reduces binding affinity to AP-1/2. The flanking sequences to the trafficking motif affect the TGN38 localisation of hybrid proteins. Working with the mouse allele TGN38a has helped understand the conservation between mammalian, rat, and mouse TGN protein sequence and function. The TGN38a trafficking motif with flanking regions is provided here in an acid form with N-terminal acetylation.</p>

<p>The SARS-CoV-2 spike protein is present on the outside of the virus particles and can bind to angiotensin-converting enzyme II (ACE2) present on the host cells. The C-terminal receptor binding domain (RBD) of the spike protein binds to the N-terminal peptidase M2 domain of ACE2. This receptor binding results in the internalisation of the virus-receptor complex and is, therefore the mechanism of entry of SARS-CoV-2 into host cells.The spike protein residues GRLQSLQTY (999-1007) from C have been identified as a T-cell epitope with a predicted HLA restriction. Immune targeting of confirmed epitopes may potentially offer protection against SARS-CoV-2 and help the development of vaccines for long-lasting immunity.</p>

<p>This peptide is recognised and cleaved by the enzyme Sortase A (SrtA) from-Staphylococcus aureus. The catalytic cysteine residue in the active site of SrtA serves as a nucleophile to cleave the peptide bond between threonine and glycine. Cleavage results in the formation of a thioacyl intermediate between the peptide and SrtA. This intermediate is then resolved by the N-terminus of an (oligo)glycine nucleophile, resulting in the creation of a new peptide bond that links the peptide and its fluorescent dye to the incoming nucleophile. This method of protein labelling is known as sortagging.5-Carboxytetramethylrhodamine (5-TAMRA) is a widely used fluorescent dye which excites at 546 nm and emits at 579 nm.</p>

<p>The Influenza Virus Nucleoprotein (311 - 325) is a component of the viral ribonucleotide complex, derived from the influenza virus and it is involved in viral replication, RNA packing and nuclear trafficking. As a monomer it contains basic residues which allow it to bind to single stranded RNA and through its flexible tail loop it has the ability to form NP oligomers.Furthermore NP is able to support the viral polymerase structurally, through associating with the two subunits PB1 and PB2, and it allows the viral ribonucleotide complex to be transported in and out of the nucleus due to its nuclear localisation and nuclear export signals.During influenza viral replication messenger RNA, viral genome RNA and complementary positive-sense RNA are produced and NP is crucial for this replication.Inhibitors of NP have potential to be used to prevent the influenza virus in humans.</p>

<p>The SARS-CoV-2 spike protein is present on the outside of the virus particles and can bind to angiotensin-converting enzyme II (ACE2) present on the host cells. The C-terminal receptor binding domain (RBD) of the spike protein binds to the N-terminal peptidase M2 domain of ACE2. This receptor binding results in the internalisation of the virus-receptor complex and is, therefore the mechanism of entry of SARS-CoV-2 into host cells.The spike protein residues SLIDLQELGK (1196-1205) from SARS-CoV-2 have been identified as a T-cell epitope with a predicted HLA restriction. Immune targeting of confirmed epitopes may potentially offer protection against SARS-CoV-2 and help the development of vaccines for long-lasting immunity.</p>

<p>Vasoactive intestinal peptide (VIP) is a neuropeptide found throughout the body and the central nervous system. VIP is located within cell bodies and nerve endings of the enteric nervous system, brain and pancreas. VIP neurons in the peripheral system fire to regulate blood vessels, and the  CNS innervate cerebral vasculature. VIP  binds to G protein-coupled receptors VPAC1 and VPAC2. VIP and VPAC2 are detected in circular smooth muscle cells of cerebral arterioles. VIP and VPAC1 are also found in lymphatic tissue. VIP can block inflammation, modify the Th response favouring Th2 and induce regulatory T cells. Overexpression of each receptor has been linked to various cancers.VIP administration leads to pancreatic bicarbonate-rich fluid secretion but not to the same degree stimulated by secretin. VIP stimulates insulin secretion in a glucose-dependent manner and also stimulates glucagon secretion. Studies have found that in morbidly obese patients, VIP levels are lowered and work to slow gastric and duodenal motility but increase gastric emptying. Therefore, decreasing VIP levels in obese patients may increase weight gain by accelerating gastric emptying.VIP has been well studied in pancreatic acini. VIP is a full agonist of amylase secretion and increases cyclic AMP synchronised with an increase in intracellular Ca2+ triggered by stimuli that act through cholecystokinin (CCK) or cholinergic agonists. Most cAMP increases and amylase secretion appears to be mediated via VPAC1.</p>

<p>Formyl-MIFL-acid.</p>

<p>Neuropeptide S (NPS) is a neuropeptide found in mammalian brains, primarily in neurons in the lateral parabrachial nucleus, the peri-locus coeruleus and the principle sensory 5 nucleus of the trigeminus. NPS in involved in several neuroendocrine, behavioural and inflammatory responses, including: reducing anxiety in mice- suppressing appetite- and inducing wakefulness and hyperactivity. NPS treatment can be used to improve fear extinction in mice and limit fear memory retrieval after fear reduction training, thus making it an interesting target in relation to post-traumatic stress disorder. NPS exerts its actions by binding to a G-protein coupled receptor, NPSR.</p>

<p>Biotin TAT (48-60) is a cell penetrating cationic peptide derived from the N-terminus of the Tat protein, which is a trans-activator of the transcription protein present in the human immunodeficiency virus (HIV). The 48-60 region of the TAT peptide is an arginine-rich bascic domain which as a whole has three domains that function to aid HIV through transactivation, DNA binding and nuclear transport. As a cell penetrating peptide (CPP) TAT aids in the cellular uptake of molecules and hence serves a valuable purpose in transduction methods. This property has been demonstrated through its ability of allowing toxins such as the neurotoxin Botulinum neurotoxin Type A, produced by the Clostridium botulinum type A bacteria to penetrate the skin barrier non-invasively.This peptide has a covalently bonded N-terminal Biotin tag that can be used for detection and purification and contains an N-terminal aminohexanoic acid spacer (Ahx).</p>

<p>EHD1 is a member of the C-terminal EPS15-Homology Domain-containing (EHD) protein family and is involved in recycling cell surface receptors.</p>