Peptídeos

<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-II has the conserved thiolactone macrocycle of the AIP family. Asn-3, Leu-8, and Phe-9 have been shown to be critical for activation of the agr response while inhibition relies on Leu-8 and Phe-9. The reactive thiol ester bond is only necessary for activation of the agr response. Further work may provide further AIP:AgrC inhibitors.</p>

<p>Nuclear Factor Erythroid 2-Related Factor 2 (Nrf2) and its negative regulator Kelch-Like ECH-Associated Protein 1 (Keap1) provide vital protection in maintaining cellular redox. In parallel, Nrf2 also aids the resolution of inflammation and also tissue repair. In homeostatic conditions, the transcription factor Nrf2 is controlled in a cytoplasmic complex with Keap1 with ubiquitination and protein degradation. Nrf2 has been linked to numerous cancers due to mutations affecting the binding region of Nrf2 to Keap1, resulting in Nrf2 dissociating from the complex. Nrf2 constitutively accumulates in the nucleus and activation of prosurvival genes that promote cancer cell proliferation.The Neh2 region of Nrf2 interacts with Keap1, as shown by nuclear magnetic resonance spectroscopy. The 16 amino acid peptide (AFFAQLQLDEETGEFL) (69-84) flanks the conserved ETGE motif and can replicate the binding to keap1.Therapeutics targeting the Nrf2 signalling pathway and activation of Nrf2 is a keen area of research, with many cancers being linked to Nrf2, particularly pancreatic cancer. Additionally, activation of Nrf2 has become a possible target as a treatment for COVID. Nrf2 (69-84) replicating full-length Nrf2 binding has been helpful in all cases. This Nrf2 (69-84) contains a covalently bonded N-terminal Biotin tag that can be used for detection and purification. If you would prefer the simple peptide, Nrf2 (69-84), it is available from our catalogue.</p>

<p>C-type natriuretic peptide (CNP) is a novel urinary biomarker which is part of the natriuretic peptide family. CNP is produced in the kidney and the endothelium and has been localised to renal tubules. CNP expression has also been detected in cardiomyocytes, vascular endothelium, and bone.CNP is synthesized as the precursor 103 amino acid (AA) protein, proCNP (AA 1-103), which is then cleaved into NT-proCNP (AA 1-50) and CNP53 (AA 51-103) by the intracellular endoprotease furin. CNP53 is then cleaved to give the biologically active mature form CNP22 (AA 82-103) and inactive form NT-CNP53 (51-81). CNP primarily acts as an autocrine or paracrine factor and has anti-proliferative and anti-fibrotic properties, including suppression of fibroblast proliferation and collagen production, inhibition of vascular smooth muscle cell proliferation and accelerated regeneration of endothelial cells. CNP is a vasodilator and potent venodilator and slightly elevated levels have been detected in heart failure and renal disease states. CNP has renoprotective properties and is activated during renal injury, where it helps preserve glomerular function and suppress pro-fibrotic processes. Hypoxia, cytokines and fibrotic growth factors, are stimuli for CNP production and release.CNP selectively activates the cell surface particulate guanylyl cyclase receptor B (GC-B), catalysing the conversion of GTP to the downstream second messenger, cyclic guanosine monophosphate (cGMP).</p>

<p>Mastoparan is a 14-residue cationic peptide toxin isolated from the wasp Vespula lewisii venom which shows an important potency as an antimicrobial and anticancer agent but also as a Cell Permeable Peptide.<br>Mastoparan is mainly known to be a receptor-independant and allosteric regulator of G-protein by stimulating GTPase activity.<br>Besides modulating the activity of G-protein, Mastoparan have the ability to bind other intracellular targets such as Ca2+-ATP (implicated in Ca2+ release), small GTP binding proteins rho and rac, and many others.<br>Mastoparan also belongs to the cell permeable peptide (CPP) family. As such, Mastoparan increases the membrane conductance and permeability of planar lipid bilayer and liposomal membranes which leads to enhanced the penetration of Ca2+, Na+ or K+ ions.<br>Mastoparan have also a potential antibiotic effect due to its potent antimicrobial activity which can turn Mastoparan to a potential drug for infectious diseases.<br>Some studies have also reported that Mastoparan exhibits potent anti-cancer activities toward leukemia, myeloma, and breast cancer cells with an approximately half maximal inhibitory concentration (IC50) of 9µM, 11µM and 22µM respectively.<br>Mastoparan have shown to be more specific to cancer cells than to normal cells.</p>

<p>Alyerserin-1b is a C-terminally α-amidated 23 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-1 peptides have limited structural similarity to the ascaphins from the skins of frogs of the Leiopelmatidae family. Alyteserin-1 peptides are selective at inhibiting growth activity of Gram-negative bacteria-such as Escherichia coli and show 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 less likely for resistance to develop towards them compared to conventional antibiotics.</p>

<p>PAF26 is a cell penetrating antimicrobial peptide (CP-AMP) with strong activity against fungi that cause postharvest decay in fruits, such as strains of Penicillium italicum, Penicillium digitatum, and Botrytis cinerea and is also active against Fusarium oxysporum.PAF26 has reduced toxicity to Escherichia coli and Saccharomyces cerevisiae, demonstrating selectivity towards certain filamentous fungi. PAF26 is endocytically internalized at low fungicidal concentrations and accumulates in vacuoles before being actively transported into the cytoplasm where it exerts its antifungal activity. PAF26 is not lytic or cytotoxic to human cells.</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. 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. 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. The lysine at position 9 has been acetylated, which neutralizes the positive charge on the amino acid, loosening the chromatin structure. This alteration to the accessibility of chromatin promotes the initiation of transcription. 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.This peptide contains a C-terminal GGK linker labelled with 5-Carboxyfluorescein (5-FAM), a widely used green fluorescent tag. This peptide also has an uncharged C-terminal amide.</p>

<p>Histone 4 (H4) is one of the four core histones (H2A, H2B, H3 and H4) which are essential for compacting eukaryotic DNA into the nucleosome. Due to the high lysine and arginine content, histones have a net positive charge and therefore electrostatically interact with negatively charged DNA. 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. Like other core histones, H4 has a globular domain and a flexible N-terminal domain, the histone tail, which can undergo modifications such as acetylation, methylation, phosphorylation and ubiquitination.Gene transcriptional activation or inactivation is controlled by ATP-dependent chromatin remodelling factors and histone modifying enzymes. Both processes function to alter the positioning of the nucleosome, allowing the DNA within to be either accessible to the transcription machinery or inaccessible. H4 lysine rich tail plays a role in the higher order chromatin folding.The lysines at positions 5, 8, 12 and 16 have been acetylated, which neutralizes the positive charge on the amino acid, loosening the chromatin structure. This alteration to the accessibility of chromatin promotes the initiation of transcription. Acetyl-Histone H4 (1-21) K5Ac, K8Ac, K12Ac, K16Ac-GG-[Lys(5-FAM)]-has a C-terminal GGK linker labelled with 5-Carboxyfluorescein (5-FAM), a widely used green fluorescent tag. Additionally, this peptide has an uncharged C-terminal amide and is protected from N-terminal modifications by a covalently bonded acetyl group.</p>

<p>ANP (7-20) is derived from the atrial natriuretic peptide (ANP) which is a cardiac hormone involved in maintaining cardio-renal homeostasis. This occurs through the activation of the guanylyl cyclase-coupled receptor, resulting in the increased concentration of cyclic guanylate monophosphate. Moreover its function in the processes of anti-proliferation and anti-angiogenesis allow it to take part in the cardiovascular remodelling process.ANP is a member of the natriuretic peptide family and it is encoded by the NPPA gene, located on chromosome 1. Once synthesized from the 151 amino acid pre-prohormone into its biologically active form, ANP is secreted by the atrial cardiomyocytes in the circulating forms: ANP (1-98) and ANP (99-126). This synthesis process involves the signal peptide being removed from the pre-prohormone resulting in proANP (1-126) which is converted into the circulating forms by the type II transmembrane serine protease Corin.</p>

<p>TAT-GSK'364A peptide is able to specifically mimic the binding sequence between Midline-1 (MID1) and the protein phosphatase 2A (PP2A) alpha4 complex and therefore can specifically outcompete MID1 from binding to alpha4-PP2Ac. TAT-GSK'364A therefore is useful in studying Alzheimer's disease (AD). AD is characterized by senile plaques, composed of amyloid-β (Aβ) peptides, derived from sequential proteolytic cleavage of the amyloid precursor protein (APP), and neurofibrillary tangles, composed of hyperphosphorylated tau protein.MID1 protein induces the translation of amyloid precursor protein (APP) mRNA via mTOR-eIF signalling and binds to PP2A to form the MID1-PP2A complex. PP2A is the main tau phosphatase and MID1 is a negative regulator of PP2A activity as it acts as an E3 ubiquitin ligase to promote the ubiquitin-dependent degradation of PP2A.GSK'364A contains 29-residue sequence from the alpha4 subunit (AQAKVFGAGYPSLPTMTVSDWYEQHRKYG) with an N-terminal sequence derived from HIV-TAT protein (RKKRRQRRR).</p>

<p>Galanin (mouse, rat) is 29 amino acids, 1 less than human galanin. Galanin is a widely distributed neuropeptide in the central nervous, peripheral, and endocrine systems. Galanin interacts with 3 receptor subtypes, GalR1-3. These G protein-coupled receptors are inserted into the plasma membrane. Galanin has a role in energy homeostasis. Central injections of galanin to the amygdala lead to food intake in rats.Galanin has been shown to inhibit glutamate release from the hippocampus. Glutamate has an excitatory effect in the mechanisms of epileptic seizures- therefore, galanin is considered a possible anticonvulsant.  Galanin receptor agonists with anticonvulsant properties have been developed to help seizures. Galanin has also helped provide evidence of neuronal plasticity and degradation. Galanin has been used extensively for administration to animals in vivo including rats and mice to better understand its role and help treat appetite disorders.</p>

<p>Ara h 1 is one of the major allergenic proteins from peanut (Arachis hypogaea) which contains approximately 13 potential allergenic proteins.Ara h 1 is a member of the 7/8 S globulin (vicilin) family of seed storage proteins belonging to the cupin superfamily and is the most abundant allergen present in the peanut kernel. Ara h 1 plays an important role in the allergy sensitising procedure and can be recognised by 90% of patients with a peanut allergy.This peptide represents a tryptic peptide of Ara h 1.</p>

<p>Bombesin/GRP receptor agonist derived from the pro-apoptotic protein BIM, which is a member of the BCL-2 family proteins and activates 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 BIM is a member of the BH3 molecules alongside, BIM, PUMA and NOXA which can all 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.BIM can be activated by CHOP-mediated transcription and phosphatase 2A-mediated dephosphorylation during endoplasmic reticulum stress. However when BIM is phosphorylated it undergoes degradation by the proteasome.</p>

Peptide substrate for the kallikrein-related peptidase 7 (KLK7), the most abundant KLK family protease in the stratum corneum (outermost layer of the epidermis). KLK family have been implicated in several key homeostatic processes and in skin diseases that feature impaired desquamation. Increased levels of KLK7, have been identified in the stratum corneum of patients with atopic dermatitis (AD). T-helper type 2 cytokines, including interleukin 4 (IL-4) and-IL-13, can stimulate expression of KLK7, suggesting a direct link between inflammation in AD and KLK7 levels.KLK7 cleaves its substrates after tyrosine or phenylalanine residues. This peptide contains a C-terminal 7-amino-4-methylcoumarin (AMC) fluorescent tag, which is quenched when linked to the peptide via the amide bond. AMC is cleaved from the peptide by KLK7, upon cleavage the AMC fluorescence is activated.

<p>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 (324-338) is a class I (Kb)-restricted peptide epitope of OVA. The ovalbumin fragment is presented by the class I MHC molecule, H-2Kb.</p>

<p>Binds to the cysteine rich domain of the Frizzled 7 receptor and inhibits Wnt signalling in cultured cells and stem cell function in intestinal organoids.</p>

<p>Portion of Influenza A</p>

<p>Highly specific protein tag that can be added to a protein using recombinant DNA technology. FLAG is an artificial antigen to which high affinity monoclonal antibodies have been raised, therefore allowing for highly effective protein purification by affinity chromatography as well as accurate localisation of FLAG tagged proteins within living cells, or Western blots. FLAG peptide can be used to effectively purify complexes with multiple proteins as its mild purification procedure tends not to disrupt such complexes. It can be used to obtain proteins of sufficient purity for x-ray crystallography.</p>

<p>Tetanus Toxin (1084-1099) is a protein that is derived from the single-chain polypeptide neurotoxin produced by Clostridium tetani. The neurotoxins produced by Clostridium tetani are among the most potent molecules known to humankind. Once in the body, the toxin binds to the basal lamina at the neuromuscular junction. From here, the toxin is transported to inhibitory interneurons in the spinal cord, where it prevents the release of neurotransmitters, which causes spastic paralysis.</p>

<p>Substrate peptide for C-terminal Src kinase (Csk) for use in kinase assays. Csk is a cytosolic tyrosine kinase that is closely related to the kinase Src and is a well-known negative regulator of Src family kinases. Csk has both tumour suppressor and oncogenic properties and has also been implicated in regulating blood pressure, making Csk a novel therapeutic target for hypertension disorders.</p>