Peptidi

<p>Calcitonin is a peptide hormone excreted by the thyroid parafollicular cells to regulate calcium and phosphorus levels. Calcitonin acts in opposition to parathyroid hormone (PTH) and vitamin D. Calcitonin functions by inhibiting osteoclast activity in the bones preventing calcium release- there is also inhibition of renal tubular cell reabsorption of calcium and phosphate, so they are excreted preventing a rise in levels.Calcitonin is used for as marker for detection and prognosis of nodular thyroid diseases. Medullary thyroid cancer is one example of the malignant parafollicular cells detectable with the assay, as they present with an increased calcitonin level even at an early stage.Since the discovery of calcitonin over 50 years ago the salmon sourced peptide has been used in numerous treatments including bone metastases, Paget disease, hypercalcaemia, and postmenopausal osteoporosis. The salmon calcitonin has been shown to be equivalent to human form but more active and can be synthetically generated.</p>

<p>Amyloid β-peptide (Aβ) has been identified as the key subunit of the extracellular plaques found in the brains of patients with Alzheimer's disease (AD) and Down's 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 γ-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.</p>

<p>Histone H3 (1-22) K4Me3 is derived from Histone 3 (H3) which is one of the four core histones (H2A, H2B, H3 and H4) fundamental in compacting eukaryotic DNA into the nucleosome. The nucleosome arises when 147 base pairs of DNA wrap around a H3-H4 tetramer and two H2A-H2B dimers, forming the histone octamer core. 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. Due to histones containing a large number of lysine and arginine residues they have a positive net charge which interacts in an electrostatic manner with the negatively charged phosphate groups in DNA. The transcriptional activation or silencing of the chromatin is controlled by ATP-dependent chromatin remodelling factors and histone modifying enzymes which target histone proteins. Both processes function to alter the positioning of the nucleosome, allowing the DNA it to be either available or inaccessible to the transcription machinery.Another modification process histones can undergo is biotinylation where the covalent attachment of a biotin molecule is catalysed by the enzyme biotinidase. This cleaves biocytin to generate a biotinyl-thiester intermediate. The biotinyl can then be transferred onto the histone lysine ɛ-amino group which in this case it is covalently attached to Histone 3. Overall the biotinylation sites identified in histone 3 are: K4, K9 and K18. The presence of biotinylated histones have been detected in human cells such as lymphocytes and lymphomas.Lysine 4 of H3 (1-22) has been tri-methylated.</p>

<p>Pro-opiomelanocortin (POMC)-derived peptides act on neurons expressing the Melanocortin 4 receptor (MC4R) to reduce body weight. Setmelanotide is a highly potent MC4R agonist that leads to weight loss in diet-induced obese animals and obese individuals with complete POMC deficiency.The endogenous ligand alpha-melanocyte-stimulating hormone (alpha-MSH) for MC4R has been shown to have a much lower affinity than Setmelanotide, explaining some of the drug's potency. Administration of Setmelanotide to wildtype mice resulted in significant weight loss while  MC4R knockout mice fail to respond. Setmelanotide is in numerous clinical trials and shows promising results. Patients with POMC defects upstream of MC4R show more significant responses to treatment than those with MC4R deficiency or obese controls.</p>

<p>Histone deacetylases (HDACs) are a family of enzymes which are highly evolutionary conserved across all eukaryotes. HDACs modify histones by removing acetyl groups from the tail regions. Histone deacetylation is generally associated with reduced gene expression due to a more compact chromatin state less accessibility for transcription factors (TFs). HDACs are essential for many physiological processes including development and cellular homeostasis. They also play an important role in disease states, including neurodegenerative disorders, genetic diseases and cancers.This peptide is the fluorogenic substrate for assaying histone deacetylase (HDAC) activity in a two-step enzymatic reaction. The assay consists of the initial lysine deacetylation by HDAC followed by the release of the fluorescent group by trypsin. Fluorescence can be detected upon fluorophore release.</p>

<p>Peptide derived from the Gastric inhibitory polypeptide (GIP), an inhibiting hormone of the secretin family of hormones. While GIP is a weak inhibitor of gastric acid secretion, its main role is to stimulate insulin secretion - in a glucose-dependent mechanism. Therefore, GIP is referred to as a glucose-dependent insulinotropic peptide.GIP is derived from a 153-amino acid pro-protein encoded by the GIP gene and circulates as a biologically active 42-amino acid peptide. It is synthesised by K cells, which are found in the mucosa of the duodenum and the jejunum of the gastrointestinal tract. GIP receptors are seven-transmembrane proteins found on β-cells in the pancreas. These β-cells are those that are able to simultaneously detect glucose and release insulin as a result to GIP binding.The clinical relevance of GIP is related to type 2 diabetes mellitus (T2DM)- studies have found that T2DM diabetics are unresponsive to GIP and have lower levels of GIP secretion after a meal when compared to non-diabetics. In research involving knockout mice, it was found that absence of the GIP receptors correlates with resistance to obesity.</p>

<p>Trans-activator of transcription protein (Tat) (47-57) is a cell penetrating cationic peptide derived from the N-terminus of the Tat protein from the human immunodeficiency virus (HIV). Chimerin 1, (CHN1) is a GTPase activating protein specific for RAC GTP-binding proteins, expressed primarily in the brain. CHN1 is involved in signal transduction and is a direct effector of proteins involved in axon guidance. CHN1 is transferred to the plasma membrane and negatively regulates Rho-family small GTPases RAC1 and CDC42, to cause morphological changes to axons by pruning the ends of axon dendrites. As a cell penetrating peptide (CPP) TAT aids in the cellular uptake of molecules. TAT (47-57) can be used to deliver proteins, fluorophores, chelators and DNA to target cells.</p>

<p>[Tyr0]-Apelin-13 is derived from the apelin peptide which acts as a ligand for the apelin receptor (APJ) G protein coupled receptor and is a substrate for angiotensin converting enzyme 2. Preprapelin, encoded for by APLN located on Xq25-26.1, is cleaved to form either apelin-36 or apelin-17, 12 and apelin-13. As a member of the adipokine hormone family, which are involved in processes such as vascular homeostasis and angiogenesis, apelin is secreted from adipose tissue.Apelin has been found to be expressed in the spinal cord and the human brain and when performing immunohistochemistry it was observed that Apelin-17 is significantly expressed in the human heart, brain, lungs and endothelial cells.Both apelin and the apelin receptor are widely distributed around the body thus apelin has been found to be associated with cardiovascular diseases, obesity, diabetes and cancer. Studies exploring myocardial infarction showed there to be greater apelin mRNA expression during human heart failure compared to in healthy tissue. Apelin protects against heart failure due to, the pyroglutamyl form of apelin, playing a role in decreasing infarct size of myocardial infarctions. Furthermore in rats with hypertension, the expression of apelin and APJ was decreased.</p>

<p>Heptapeptide containing a cysteine residue whose thiol group makes it vulnerable to a range of oxidative modifications.</p>

<p>Natural cleavage product of GLP-1 which, unlike GLP-1, does not affect either insulin secretion or glucose homeostasis.  GLP-1(9-36) has low affinity for, and acts as an antagonist to, the GLP-1 receptor.GLP-1 (9-36) does however display unique biological activities such as beneficial cardiovascular effects and reducing the production of reactive oxygen species (ROS). GLP-1 (9-36) also exerts important physiological effects on neuronal plasticity in the hippocampus, and inhibits chemokine-induced migration of human CD4-positive lymphocytes.GLP-1 (9-36) is formed from the breakdown of biologically active but highly unstable GLP-1 (7-36) amide by the ubiquitous serine protease, dipeptidyl peptidase-IV (DPP-IV).</p>

<p>An anti-microbial peptide (AMP) of the cathelicidin family, originally discovered in pig neutrophils. Tritrpticin has potent and broad anti-microbial activity against Gram-positive and Gram-negative bacteria, some fungi, and protozoa.Tritrpticin is thought to exist in a range of conformations in solution, and recognise its targets with high selectivity and efficiency whilst displaying low haemolytic activity. The peptides three sequential tryptophan residues flanked by two prolines and four arginines are important for the peptides interaction with membranes and for its mechanism of action. The presence of these three tryptophan and four arginines residues, also class Tritrpticin as a member of the Arg/Trp-rich family of AMPs.</p>

<p>SMAC/DIABLO -TAT (48-60)-[Lys] is a pro-apoptotic peptide that is derived from the mitochondrial protein known either as Second Mitochondria-Derived Activator of Caspases (Smac) or Direct IAP Binding Protein with low isoelectric point, pI (DIABLO). During apoptosis the mitochondria has increased permeability to Smac/DIABLO, which causes the protein to diffuse into the cytosol. Here, Smac/DIABLO adheres to Inhibitors of apoptosis proteins (IAPs) and prevents them from binding to caspases, which in turn accentuates apoptosis.TAT (48-60) is present due to its properties as a cell penetrating cationic peptide (CPP). It 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). As a CPP, TAT (48-60) is able facilitate the delivery of the Beclin scrambled protein across the plasma membrane.This peptide has an additional lysine attached to the C-terminus of the TAT (48-60) sequence.</p>

<p>Tachykinins are important neuropeptides throughout the nervous system involved in various roles including smooth muscle activity. Substance P is the natural ligand for neurokinin 1 (NK1) tachykinin receptor. Septide was originally identified from the C-terminus substance P and found to be a selective agonist of NK1 tachykinin receptor. Septide is a potent agonist able to stimulate muscle contraction in various models but not all. However, septide consistently lacks a high affinity for the NK1 tachykinin receptor compared to substance P or other applicable agonists. A 'septide sensitive' receptor is speculated, or it could be a conformation of NK1 tachykinin receptor. Further work is required to establish septide function and role in the nervous system. Septide is provided here with an N-terminal pyroglutamic acid to aid this investigation as is standardly used within the literature.</p>

<p>Acetyl-(Arg)9, derived from (Arg)9 is a cationic cell-penetrating peptide consisting of 9 arginines. Arginine rich CPPs enter cells in a passive manner through membrane multilamellarity and fusion. (Arg)9 can function to deliver specific molecules to target cells and can be used for drug delivery purposes.Peptide is labelled with an N-terminal 5-carboxyfluorescein (5-FAM), a widely used green fluorescent tag.</p>

<p>Originally identified in Heloderma horridum horridum (Mexican beaded lizard), exendin-3 shares homology with vasoactive intestinal peptide (VIP), secretin, helospectin I and II and helodermin. Exendin-3 increases cellular cAMP levels and amylase release from pig pancreatic cells.Truncated exendin-3 is a potent and selective GLP-1 receptor antagonist. It inhibits cAMP production and insulin release induced by GLP-1, exendin-3, and exendin-4. It also blocks the inhibitory effect of GLP-1 on food intake in rats. Exendin 3 (9-39) amide is being considered for clinical use in obese patients. This is based on the extensive and consistent data demonstrating its effectiveness as a tool to improve fasting and postprandial levels of glucose and glucagon.</p>

<p>Acetyl-Claudin-3 is derived from the tight junction protein Claudin-3 which is encoded by the CLDN3 gene located on chromosome 7q11.23 and can be found within epithelial cell to cell contacts. Structurally, the Claudin family are transmembrane proteins containing two extracellular loops and are involved in maintaining cell polarity and controlling paracellular ion flux.During cancer research reduction in the number of Claudins has been associated with tumour formation. This could be explained using Claudin role in maintaining cell detachment and migration although cancers such as breast and prostate have shown to overexpress both Claudin- 3 and Claudin-4. Similarly in ovarian cancer overexpression of Claudin 3 and 4 is thought to increase the motility of tumour cells and their survival through basement membrane degrading matrix metalloproteinase activation.Both Claudin 3 and 4 have potential to be used as diagnostic markers and their two extracellular loops may be used as targets for antibodies. As receptors for the Clostridium perfringens enterotoxin, Claudin 3 and 4 may have further use in targeting the enterotoxin as a therapeutic for ovarian cancers.</p>

<p>Segment 18-39 of adrenocorticotropic hormone (ACTH). ACTH, also known as corticotropin, is a cleavage product from a larger precursor proopiomelanocortin (POMC). This 39 amino acid-peptide hormone is produced in the anterior pituitary gland upon stimulation by the corticotropin releasing hormone from the hypothalamus in response to stress. It stimulates the secretion of steroid hormone, specifically glucocorticoids in the adrenal cortex by acting through a cell membrane receptor (ACTH-R). In mammals, the action of ACTH is limited to those areas of the adrenal cortex in which the glucocorticoid hormones cortisol (hydrocortisone) and corticosterone are formed. ACTH has little control over the secretion of aldosterone, the other major steroid hormone from the adrenal cortex.</p>

<p>Albumin (50-62) Bovine is derived from the globular protein Albumin and is found in the blood plasma of humans (known as Human Serum Albumin, HSA) where it serves to maintain plasma pressure and nutritional balance. Another role it carries out is the transportation of bound molecules through the blood. Bovine serum albumin (BSA), composed of 583 amino acids, is very similar to HSA thus allowing BSA to be used as a successful model and a standard protein in laboratory experiments.Although BSA and HAS share homology in their three domains, I, II and III, BSA contains 2 tryptophan whereas HAS only contains 1 tryptophan residue. In agriculture the presence of the albumin protein has been used to assess the health of cows to ensure that a suitable quality of milk and meat are produced. Moreover it is important to detect bovine albumin in food and pharmaceutical products due to it being an allergenic protein.In agriculture the presence of the albumin protein has been used to assess the health of cows to ensure that a suitable quality of milk and meat are produced. Moreover it is important to detect bovine albumin in food and pharmaceutical products due to it being an allergenic protein.</p>

<p>EBV BZLF1 (40-48) (HLA-E) is an immunodominant CEF control peptide that is derived from the Epstein-Barr virus (EBV). EBV targets B cells, which can cause lytic infection and the consequent death of these cells. Natural killer (NK) cells, invariant (iNKT) cells, CD4T cells and CD8 T cells are essential to control the action of EBV-infected cells. EBV BZLF1 (40-48) (HLA-E) is defined as a CEF control peptide due to its antigenic properties. Clinically, these peptides are suitable epitopes for CD8+ T cells and can be used to stimulate the release of IFNg. HLA-E refers to the cell HLA type that this peptide acts on.The BZLF1 protein mediates the transition from the latent stage to the lytic stage of the virus's infection. The lytic stage of the γ herpesvirus has been found to be associated with human carcinogenesis and BZLF1's ability to activate p53 may allow it to induce DNA damage. Structurally it is similar to the leucine zipper family of transcriptional factors.</p>

<p>PD-1 (24-38) peptide is derived from the programmed cell death-1 (PD-1) which interacts with its ligand, PD-L1 to regulate immune homeostasis. PD-1 and its ligand PD-L1 are critical in regulating T cell activation, tolerance and immuno-pathology. PD-1 is an immune checkpoint and guards against autoimmunity through two mechanisms. First, it promotes apoptosis of antigen-specific T-cells in lymph nodes. Second, it reduces apoptosis in regulatory T cells.Several types of cancer cells overexpress PD-L1 in order to escape from the PD-1/PD-L1 immuno-surveillance mechanism. Consequently PD-1 inhibitors and PD-L1 inhibitors could be used as a therapeutic in the treatment of cancers.</p>

<p>Proapoptotic peptide KLA is a cationic amphipathic peptide that disrupts the mitochondrial membrane. Proapoptotic peptide KLA cannot of its own accord cross eukaryotic cell membranes and is therefore not toxic to the latter. However, KLA has been fused to various protein transduction domains (PTDs) to study its effects in cells. With the fusion of PTDs such as penetratin, KLA becomes highly toxic to cancer cells, it disrupts the mitochondrial cell membrane releasing cytochrome C. This induces cytotoxicity and triggers apoptosis while not effecting normal cells. This selectivity makes KLA-fusion peptides an ideal candidate for further research into cancer treatments as it provides targeted delivery of a highly toxic peptide that only seems to effect cancerous cells. Proapoptotic peptide KLA is provided here to research grade quality, potential PTDs are also available in our catalogue.</p>

<p>Endogenous peptide GPR83 agonist derived from processing of precursor protein, proSAAS, a 26-kDa protein encoded by the PCSK1N gene (chromosomal localization Xp11.3 in humans). It is widely expressed in a number of species where it is involved in feeding, stress modulation and addiction and reward circuits.</p>

<p>Peptide derived from gp100, a type 1 transmembrane glycoprotein and a homologue of the melanocyte specific protein Pme117. Gp100 may therefore constitute a useful target for specific immunotherapy against melanoma.</p>

<p>This peptide represents the reserve sequence of β-amyloid 25-35 (Aβ 25-35) and is used as an inactive control peptide.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 γ-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.</p>

<p>Soluble, oligomeric forms of β-amyloid (Aβ) are neurotoxic and are the primary cause of neuronal injury and cell death in Alzheimer's disease (AD). SEN304 is a powerful inhibitor of Aβ aggregation and toxicity and therefore may be therapeutic for AD. SEN 304 can bind directly to Aβ(1-42), delay β-sheet formation and promote aggregation of toxic oligomers into a nontoxic form.</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-2 agonist peptide mimics the sequence of the 'tethered ligand' and is therefore capable of activating the receptor independently of N-terminal proteolysis.SLIGRL-NH2 inhibits the development of airway eosinophilia, hyper-responsiveness and displays bronchodilator activity in allergic mice and also facilitates gastrointestinal transit in mice-in vivo.PAR activation has been linked to inflammation, therefore compounds that mimic or interfere with the PAR-activating processes are attractive therapeutic candidates.</p>

<p>SARS-CoV-2 NSP13 (336-350)</p>

<p>H-STMSIT-OH peptide, corresponding to RNase A 77-82 (Chain A of bovine pancreatic ribonuclease) has been published to have amyloidogenic properties, and under certain conditions H-STMSIT-OH hexapeptide forms amyloid fibrils. Please also see CRB1001321, which you can use as a negative control in amyloid formation experiments.</p>

<p>Myocarditis is an inflammatory heart disease often associated with a previous viral infection. Evidence has suggested that myocarditis may be due to autoimmune responses directed against cardiac tissue. The inflammatory immune response caused after infection may break tolerance by mechanisms of molecular mimicry, bystander activation, and loss of immune regulation. Experimental autoimmune myocarditis (EAM) is a model of inflammatory heart disease generated by immunizing susceptible rats or mice with cardiac myosin or its myocarditic epitopes. In the EAM model, cellular infiltrates consist primarily of T cells and macrophages, and T lymphocytes responsive to cardiac myosin can transfer disease. Cardiac myosin is a large peptide, which is composed of two H chains and two pairs of L chains. Proteolysis of myosin yields three subfragments including a globular head or subfragment 1 (S1) region, an alpha helical coiled coil rod comprised of subfragment 2 (S2), and light meromyosin (LMM). In the Lewis rat, the S2 subfragment has been shown to produce the most severe myocarditis.</p>

<p>The gp91 ds-TAT peptide is composed of a gp91phox sequence conjugated to the human immunodeficiency virus-TAT peptide. The TAT sequence facilitates its entry into all cells, hence it is a cell-penetrating peptide. The gp91 peptide is the haem binding sub-unit of the superoxide-generating NADPH oxidase. As a result, the gp91 ds-TAT peptide can be used as a selective inhibitor of NADPH oxidase assembly.Recent studies have shown that gp91 ds-TAT can increase blood nitric oxide bioavailability in hind limb ischaemia and reperfusion by inhibiting NADPH oxidase.</p>

<p>PMX 53 is a potent antagonist of CD88, a G protein-coupled receptor for C5a (complement protein). C5a is a protein fragment released from cleavage of complement component C5 by protease C5-convertase into C5a and C5b fragments. C5a, the other cleavage product of C5, acts as a highly inflammatory peptide, encouraging complement activation, formation of the MAC, attraction of innate immune cells, and histamine release involved in allergic responses. The origin of C5 is in the hepatocyte, but its synthesis can also be found in macrophages, where it may cause local increase of C5a. C5a is a chemotactic agent and an anaphylatoxin- it is essential in the innate immunity but it is also linked with the adaptive immunity. The increased production of C5a is connected with a number of inflammatory diseases.By antagonising the C5a receptor, PMX can be used to modulate inflammatory responses, obesity, development and cancers.</p>

<p>Peptide H-YDPSLKPLSVSYDQATSLR^-OH is a Research Peptide with significant interest within the field academic and medical research. This peptide is available for purchase at Cymit Quimica in multiple sizes and with a specification of your choice.</p>

<p>Peptide Ac-SQNYPIVQ-OH is a Research Peptide with significant interest within the field academic and medical research. This peptide is available for purchase at Cymit Quimica in multiple sizes and with a specification of your choice.</p>

<p>Histone 3 (H3) is one of the four core histones (H2A, H2B, H3 and H4) fundamental in compacting eukaryotic DNA into the nucleosome. The nucleosome arises when 147 base pairs of DNA wrap around a H3-H4 tetramer and two H2A-H2B dimers, forming the histone octamer core. 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. The transcriptional activation or silencing of the chromatin is controlled by ATP-dependent chromatin remodelling factors and histone modifying enzymes which target histone proteins. Both processes function to alter the positioning of the nucleosome, allowing the DNA it to be either available or inaccessible to the transcription machinery.The lysine at position 4 of this peptide has been tri-methylated and it is implicated in studies that this modification may remodel the chromatin so that it is more accessible to transcription factors, which may ultimately increase the level of gene expression. Moreover, the serine at position 10 has been phosphorylated, and studies have suggested that this may induce chromatin condensation, and subsequently repress transcription and gene expression.Histone H3 (1-20) K4Me3, pS10-GG-[Lys(5-FAM)] has a C-terminal GKK linker labelled with 5-Carboxyfluorescein (5-FAM), a widely used green fluorescent tag.</p>

<p>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.It contains 5-Carboxyfluorescein (5-FAM), a widely used green fluorescent tag.</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 LIDLQELGKY (1197-1206) 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>Arginine vasopressin (AVP) is a neurohypophysial hormone that is synthesized in the supraoptic nucleus and paraventricular nucleus of the hypothalamus. The major function of AVP is to regulate extracellular fluid volume and electrolyte homeostasis via its anti-diuretic action. It is also a vasoconstrictor and pressor agent. AVP is important to the central nervous system (CNS) and also has physiological actions in the peripheral organs, such as the kidney, heart and vascular beds.</p>

<p>Human γHV Epstein-Barr virus (EBV) is host-specific, making it challenging to study. Evidence suggests EBV infection provides an enhanced immune response against other future heterologous infections. Murid herpesvirus 4 (MuHV-4) in mice can be used as a model to help understand herpesviruses. The peptide provided here (ORF65131-140) has been used in CTL assays to show that MuHV-4 improves the effector CD8+ T cells response against a heterologous virus. MuHV-4 ORF65131-140 epitope can stimulate interleukin production ex vivo and be detected by tetramer staining to MHC. Further work with MuHV-4 ORF65131-140 could be crucial for understanding the reactivity of the human immune system to other viruses after infection with γHV Epstein-Barr virus (EBV).</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 biotin tag to the incoming nucleophile.- This method of protein labelling is known as sortagging.This peptide contains an N-terminal biotin tag for detection and purification.</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 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-TAMRA, a widely used red fluorescent reagent ideal for peptide labelling and detection. The excitation/emission for this reagent is 555 nm/580 nm.</p>

<p>The RGD peptide is a ligand for cell-surface integrin receptors, which are used by most cells to attach to and sense the extracellular environment and to establish a cytoskeleton. RGD peptide can be attached to biologically important molecules, such as nanoparticles, to enable active targeting of drugs or gene delivery. Model substrates presenting immobilised RGD peptide can be used to promote the adhesion and spreading of cells which have been engineered to expresses integrin receptors such as the platelet cell-surface integrin receptor, alphaIIbβ3. Cells growing in these conditions appear to have well developed cytoskeletons suggesting that binding to the integrin receptor mediates biologically relevant adhesion and RGD substrates are able to support cell survival. Peptide is labelled with an N-terminal 5-carboxyfluorescein (5-FAM), a widely used green fluorescent tag.</p>

<p>This 19 amino acid fragment of myelin basic protein (MBP) can induce experimental allergic encephalomyelitis (EAE) in Lewis rats. EAE is the most commonly used experimental model for studying the human inflammatory demyelinating disease, multiple sclerosis (MS).MBP is an integral component of myelin found in the central nervous system (CNS). MBP is considered vital for the development and stability of the myelin sheath where it plays a role in membrane adhesion. MPBs constitute an extraordinarily varied collection of splice isoforms which show a myriad of post-translational modifications. MBP may be targeted by auto-antibodies in diseases such as multiple sclerosis. The low affinity of MBP (1-9) peptide for MCH class II molecules may result in MBP autoreactive T cells escaping central-tolerance, where self-reactive T cells are usually eliminated.</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 biotin tag to the incoming nucleophile.- This method of protein labelling is known as sortagging.This peptide contains an C-terminal biotin tag for detection and purification.</p>

<p>SPA4 is a surfactant protein-A (SP-A)-derived peptide which is an antagonist of toll-like receptor-4 (TLR4). SP-A and TLR4 have been identified as important pathogen-pattern recognition receptors (PPRRs). SP-A represents the majority of SPs and plays a key role in fighting pathogens and down-regulating inflammation, whereas TLR4 recognises pathogens and endogenous stress proteins and induces the inflammatory and adaptive immune responses.Over-activation of TLR4 induces inflammatory response via NF-KB and TNF-α cytokine. SPA4 has been shown to bind to TLR4 and inhibit the release of TNF-α in response to the most potent TLR4-ligand: Gram-negative bacteria-derived lipopolysaccharide (LPS), however SPA4 does not interfere with LPS binding to TLR4. The suppression of LPS-TLR4 signalling by SPA4 peptide alleviates inflammatory response.</p>

<p>Fluorescently labelled substrate for the severe acute respiratory syndrome coronavirus main protease (SARS-CoV Mpro).- The substrate sequence is derived from residues P4-P5' of the SARS-CoV Mpro-N-terminal autoprocessing site which has the sequence AVLQSGFRK. SARS-CoV Mpro is a key antiviral target.This peptide contains a highly fluorescent N-terminal 7-methoxycoumarin fluorophore (Mca) and a 2,4-dinitrophenyl (Dnp) quencher. Mca is efficiently quenched by resonance energy transfer to the 2,4-dinitrophenyl group when the peptide is intact, however upon cleavage of the peptide by Mpro, the Mca group and the Dnp quencher are separated and fluorescence can be detected. This therefore represents a useful tool for investigating Mpro activity.</p>

<p>IRBP (161-180) derived from the interphotoreceptor retinoid-binding protein (IRBP), present in the interphotoreceptor matrix and is expressed by cone and rod photoreceptors in the eye. IRBP is involved in retinoid delivery and protects retinal cells from oxidative stress.In retinitis pigmentosa patients, IRBP can be subjected to mutations resulting in a non-secreted form of IRBP to be produced. Furthermore IRBP gene mutations have been associated with high myopia and retinal dystrophy.The expression of IRBP is reduced in diabetes patients which may lead to visual cycle misfunction and the photoreceptors can be vulnerable to damage.</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 (466-480) is an epitope candidate with various predicted 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>Venom peptidomes and proteomes have yielded significant novel drug discoveries. The non-disulphide bridge peptides (NDBPs) have become a particular focus due to their large range of structures as well biological activity while retaining high specificity.AcrAP2 was identified as a NDBP in A. crassicauda within highly conserved family of proteins. Data shows it has antimicrobial activity against bacteria and yeast while also capable of haemolysing horse erythrocytes. However, AcrAP2 did not affect the growth of cancerous cell lines tested. Therefore, this peptide could be a useful model for modification to improve its potency. Furthermore, it may allow researchers to identify specific targets in disease pathways for new drug designs. A significant example of this, bradykinin-potentiating peptide Captopril® manages hypertension and originated from the conserved NDBP family.</p>

<p>Sal-like4 (SALL4) derived peptide able to antagonise the SALL4-NuRD complex in hepatocellular carcinoma, turning SALL4 from a dual transcription repressor-activator to a singular transcription activator. Displays antitumour effects in xenograft mouse models.</p>

<p>TMPRSS4 (199-207) fluorogenic peptide</p>