Peptídeos

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The peptide Des-n-octanoyl-[Ser3]-ghrelin (DOG) is a synthetic analogue of ghrelin, the only known natural ligand for the growth hormone secretagogue receptor. DOG binds to the ghrelin receptor and activates it, thereby stimulating growth hormone release from the anterior pituitary gland. In a rat model, DOG counteracts weight gain caused by high-fat diet. It also increases insulin sensitivity in diabetic rats and acts as an appetite suppressant in non-diabetic rats. As such, this peptide has potential as a therapeutic agent for obesity and diabetes.

Ovalbumin (OVA) is the primary protein in egg-white, and is involved in initiating food allergies and asthma. It is a highly immunogenic protein and can be used for peptide conjugation in the development of antibodies.OVA (323-339) is a class I (Kb)-restricted peptide epitope of OVA. The ovalbumin fragment is presented by the class I MHC molecule, H-2Kb.

Angiotensin 1-7 (Ang-(1-7)) is a component of the renin angiotensin system RAS. Ang-(1-7) is produced by angiotensin-converting enzyme 2 (ACE2), from the angiotensin II (Ang-II) peptide, as well as by prolylendopeptidase (PEP) and neutral endopeptidase (NEP) which produce Ang-(1-7) directly from angiotensin I (Ang-I).Ang-(1-7) broadly opposes Ang-II actions. Ang-(1-7) has vasodilatory and anti-oxidative effects, and exerts protective actions in hypertension, diabetes, and other cardiovascular disorders, Ang-(1-7) therefore represents a promising therapeutic target for cardiovascular and metabolic diseases. Ang-(1-7) exerts its actions via its G-protein-coupled receptor, Mas. This novel arm of the RAS has effects that counterbalance those mediated by the classical ACE/Ang-II pathway.

Glucagon (1-29)-[Lys(AF647)] is derived from glucagon, which is a peptide hormone secreted by alpha cells located in the islet of Langerhans region of the pancreas. Glucagon is an essential catabolic hormone that is responsible for the regulation of blood glucose levels. Once released into the bloodstream, glucagon stimulates the production of hepatic glucose, which means it is considered to be a glucose-mobilizing agent. Excessive levels of glucagon can result in the development of hyperglycaemia, since the action of glucagon results in abnormally high blood glucose levels.This peptide contains AF647, structural analog to Alexa Fluor® 647 which is a widely used far-red fluorescent dye.

Fluorogenic substrate for thrombin that when in its intact state does not fluoresce, however upon cleavage by thrombin in 2 successive steps, Rhodamine 110 is released to allow fluorescence.Thrombin is a multifunctional serine protease and is the principal enzyme of hemostasis. It catalyzes the conversion of fibrinogen to fibrin and activates procoagulant factors V, VIII, XI, and XIII. When bound to thrombomodulin, it activates protein C, an anticoagulant zymogen. Thrombin also activates platelets, regulates endothelial cell function, and has a host of direct actions on other cells. Thrombin has been found to act as a mediator of vascular dysfunction and inflammation in both the peripheral and the central nervous systems. Thrombin contributes to the development of cardiovascular disease, atherosclerosis and diabetes and promotes vascular dysfunction, inflammation, and neurodegeneration. Thrombin is elevated in the brains of people with Alzheimer's disease (AD) and therefore may be a therapeutic target in AD.

Alpha-2-antiplasmin (alpha2AP), a member of the serine protease inhibitor (SERPIN) superfamily, is the main inhibitor of the fibrinolytic enzyme plasmin as well as an inhibitor of trypsin, elastase, and C protein. It plays a crucial role in reducing plasmin production and activity and thus inhibiting fibrinolysis.alpha2AP is synthesized in the liver and secreted as a single-chain glycoprotein, containing 11-14% carbohydrate, with a methionine (Met) as its N-terminus (Met-alpha2AP). The N-terminus of alpha2AP is involved in the incorporation of alpha2AP into a clot and the C-terminus is involved in the initial interaction of alpha2AP with plasmin(ogen). Circulating alpha2AP undergoes both N-and C-terminal modifications, which alter its activity. Increased concentrations of a2AP are associated with a higher risk of cardiovascular diseases.

Substance P (SP) is a peptide that is highly conserved across the animal kingdom and is involved in a number of inflammatory and growth promoting processes. SP has a net positive charge at physiological pH, it is an amphiphilic peptide with positively charged residues at the N-terminus and hydrophobic residues at the C-terminus, this controls how it interacts with cell membranes. SP is relatively stable in plasma (several hours) but has a short half-life in tissues (seconds/minutes).SP is encoded by the TAC1 gene and is a member of the tachykinin peptide hormone family. SP is expressed by many cell types including: neurons- astrocytes- microglia- epithelial cells- endothelial cells- immune cells such as T cells and macrophages- dendritic cells and eosinophils and some stem cells and progenitor cells. The huge variety of cell types expressing SP suggest it is involved in a wide variety of physiological and pathophysiological functions.SP mediates its functions by interacting with members of the neurokinin (NK) family of G protein-coupled receptors with high selectivity. Among these, SP binds to NK1R with the highest affinity, this receptor is expressed in a wide range of tissue types.[5-FAM]-Substance P contains 5-Carboxyfluorescein (5-FAM), a widely used green fluorescent tag.

GPS1573 is a potent and dose-dependent peptide antagonist of adrenocorticotrophic (ACTH) -stimulated melanocortin type 2 receptor (MC2R). Along with GPS1574, GPS1773 is an ACTH analogue and as such antagonises MC2R in the nanomolar range.The clinical relevance of GPS1573 is related to Cushing's disease and syndrome, which are both associated with a hypercortisolemic state. Selective antagonism of MC2R using GPS1573 may be a novel treatment modality for Cushing's disease and syndrome.

Insulin is a peptide hormone produced by β cells of the pancreatic islets that regulates carbohydrates metabolism. It is a heterodimer of an A-chain and a B-chain, which are linked together by disulfide bonds. Insulin stimulates the absorption of glucose from the blood into fat, muscle and liver cells where it is converted into either glycogen or fat.Insulin is secreted in the blood as a response to high level of blood glucose resulting in enhanced glucose uptake and metabolism in the cells so to reduce blood glucose levels. Circulating insulin also affects the synthesis of proteins in many tissues. Low blood insulin levels result in catabolism, particularly of reserve body fat. A decrease or absence of insulin activity results in diabetes mellitus, a condition of high blood sugar level (hyperglycaemia).N-terminal chain B labelled with AF488. AF488 dye is a bright, green-fluorescent dye with excitation maxima around 490 and emission maxima around 525. AF488 dye is pH-insensitive over a wide molar range.

This C-terminal Sortagging peptide acts as a (oligo)glycine nucleophile in the final steps of a sortagging protein labelling reaction. This reaction results in the [Lys(5-TAMRA)]- fluorescent moiety being attached to the C-terminus of the target protein or peptide.A substrate peptide containing the LPXTG motif 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 of the substrate peptide. Cleavage results in the formation of a thioacyl intermediate between the substrate peptide and SrtA. This intermediate is then resolved by the N-terminus of this (oligo)glycine nucleophile peptide, resulting in the creation of a new peptide bond that links the substrate peptide to this peptide and its fluorescent dye.  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.

Fragment of the angiotensin-converting enzyme 2 (ACE2) peptidase domain (PD) alpha1 helix, a domain important for the interaction of ACE2 with the severe acute respiratory syndrome (SARS coronavirus receptor binding domain (SARS-CoV-2-RBD). SBP1 associates with the SARS-CoV-2-RBD with nanomolar affinity and can potentially block the key mechanism by which SARS CoV-2 initiates entry into human cells.

SMAC/DIABLO-[Cys(AF647)] 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.This peptide has a C-terminal cysteine linker labelled with AF647, which is a bright, far-red-fluorescent dye with excitation between 594 nm and 633 nm.

[AF488] 6xHis Tag, composed of a hexa-histidine tag and the fluorescent dye, Alexa Fluor 488 (AF488).

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 N-terminal 5-Carboxyfluorescein (5-FAM), a widely used green fluorescent tag.

Myelin oligodendrocyte glycoprotein (MOG) is a member of the immunoglobulin (Ig) protein superfamily and is expressed exclusively in the central nervous system on the surface of myelin sheaths and oligodendrocyte processes. MOG is expressed at the onset of myelination, and therefore is a potential marker for oligodendrocyte maturation.MOG contains an extracellular domain, a transmembrane domain, a cytoplasmic loop, a membrane-associated region and a cytoplasmic tail.  MOG may function as a cell surface receptor or cell adhesion molecule.  Fifteen different alternatively spliced isoforms have been detected in humans. These are present either on the cell surface, the endoplasmic reticulum in the endocytic system, or in secreted form.The secreted form of MOG may trigger autoimmunity if released into the cerebrospinal fluid and periphery. MOG is thought to be a key target for autoantibodies and cell-mediated immune responses in inflammatory demyelinating diseases such as multiple sclerosis (MS) and is therefore widely studied in this field.The MOG (35-55) fragment is the most potent auto-antigenic region of MOG, and the most effective at inducing experimental autoimmune/allergic encephalomyelitis (EAE), an animal model that resembles MS. This peptide has a free carboxylic acid at the C-terminus, an amide version is also available in our catalogue.

This C-terminal Sortagging peptide acts as an (oligo)glycine nucleophile in the final steps of a sortagging protein labelling reaction. This reaction results in the [Cys(AF680)]- fluorescent moiety being attached to the C-terminus of the target protein or peptide.A substrate peptide containing the LPXTG motif 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 of the substrate peptide. Cleavage results in the formation of a thioacyl intermediate between the substrate peptide and SrtA. This intermediate is then resolved by the N-terminus of this (oligo)glycine nucleophile peptide, resulting in the creation of a new peptide bond that links the substrate peptide to this peptide and its fluorescent dye.  This method of protein labelling is known as sortagging.C-Terminal Sortagging-[Cys(AF680)] contains the AF680 fluorescent dye- AF680 is a bright green dye with excitation at 633 nm, well suited for flow cytometry and imagery. AF680 is particularly photostable, allowing better detection of low abundance conjugates.  C-Terminal Sortagging-[Cys(AF680)] acid is provided here. However, the amide version is also available.

The HLA-DRB1*1501 peptide, is encoded by the disease-associated MHC allele histocompatibility leukocyte antigen (HLA)-DRB1*1501 which is present on the MHC region of chromosome 6. The increased frequency of the HLA-DRB*11501 haplotype found in Multiple Sclerosis (MS) patients, may contribute to the MS phenotype through disrupting T cell repertoire selection and through the presentation of self-peptides which can be targeted by the body's autoimmune response. Moreover studies investigating the accumulation of amyloid β-peptide (Aβ) as a factor producing Alzheimer's disease (AD) pathogenicity, found that HLA-DR alleles such as DRB1*1501 demonstrate immunogenic properties. It is evident that the DRB1*1501 halotype is associated with strong Aβ-T cell responses resulting in the large production of IFN- γ and IL-17. Therefore the HLA-DRB1*1501 peptide would be beneficial in studies exploring the phenotypes of autoimmune-diseases like MS and AD.