Enzyme Modulators

<p>Peptide derived from the endothelial nitric oxide synthase which synthesises nitric oxide in order to protect endothelial cells from vascular diseases, atherosclerosis and thrombosis.</p>

<p>Human epidermal growth factor receptor 2 (HER-2)/epidermal growth factor receptor-2 (ErbB-2), is a key receptor linked to metastasis in tumours. The oncogenic ErbB-2 receptor has intrinsic receptor tyrosine kinase (RTK) activity. The receptor is activated by ligand binding which induces receptor dimerization. These RTK complexes can activate mitogen-activated protein kinase (MAPK) and phosphoinositol 3'-kinase (PI3K)/Akt pathways. This peptide has been identified as a substrate for HER-2/ErbB-2 as it is phosphorylated upon receptor activation and therefore acts as a marker for receptor activation in kinases assays.</p>

<p>This peptide is phosphorylated by Janus kinase 1 (JAK1) and is an ideal substrate for use in kinase assays. The JAK family of kinases is essential for the signalling of a host of immune modulators in tumour, stromal, and immune cells where they are highly expressed. JAK family proteins mediate the signalling of the interferon (IFN), IL-6, and IL-2 families of cytokines.JAK kinases are associated with cytokine receptors. Cytokine binding to these receptors results in activation of JAK kinases and receptor phosphorylation. Phosphorylated cytokine receptors recruit STAT proteins, which are then phosphorylated by the activated JAK kinases. Phosphorylated STAT proteins form homo- and hetero-dimers that translocate into the nucleus and function as transcription factors.This JAK1 substrate peptide contains an N-terminal Glycine-residue and a phospho-tyrosine-residue.</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.</p>

<p>A glycogen synthase kinase 3β- (GSK3β-) / crosstide fragment representing the phosphorylation site on GSK3β-. GSK3β- is a serine/threonine kinase which regulates glycogen synthase activity and is a key mediator of vertebrate development, tumourigenesis and cell differentiation. GSK3β- is phosphorylated by activated AKT/protein kinase B on serine 9- promoting its inactivation.</p>

<p>Amino acids 487-496 of Poly(ADP-ribose) polymerase 1 (PARP1). PARP1 is a nuclear DNA repair enzyme that binds to DNA when damage is detected. PARP1 coordinates double and single strand break repair by first cleaving NAD+ into nicotinamide and ADP-ribose, and then synthesising poly-(ADP-ribose) (PAR) chains from ADP-ribose on target proteins (PARylation). PARylation of histone proteins mediates relaxation of the chromatin and recruitment of DNA-break repair enzymes.PARP1 can also act as a transcriptional co-activator, modulating the expression of itself and many other genes by direct binding to or PARylation of enhancers and promoters. PARP1 is also involved in maintaining mtDNA.PARP1 belongs to the PARP family which has 7 known and 10 putative members. PARP1 accounts for &gt;85% of the PARP activity in cellular systems.</p>

<p>LRRKtide (also called moesin) is a peptide substrate for leucine-rich repeat kinase 2 (LRRK2). The sequence of LRRKtide has been derived from the ERM proteins: Ezrin (amino acids 561-573), radixin (amino acids 558-570) and moesin (amino acids 539-553). These proteins influence cytoskeletal dynamics by anchoring the cytoskeleton to the plasma membrane. LRRK2 phosphorylates LRRKtide at its Thr558 site. This peptide contains the phosphorylated threonine residue.LRRK2 is a large, ubiquitous protein of unknown function. LRRK2 has GTPase and kinase activity, and is located in multiple areas of the cell, associated with intracellular membranes and vesicular structures- suggesting LRRK2 may be involved in several cellular pathways. LRRK2 is also found in most organs and mutations in LRRK2 have been identified in Parkinson's disease.The threonine residue at position 9 of this peptide has been phosphorylated.</p>

<p>A protein kinase G selective substrate for use in kinases assays, with a preference for PKG Ialpha over PKG II. PKG is a serine/threonine-specific protein kinase activated by cyclin guanosine monophosphate (cGMP). PKG is involved in several signalling pathways including: smooth muscle relaxation, platelet function, cell division, nucleic acid synthesis and sperm metabolism.</p>

<p>Substrate peptide for protein tyrosine phosphatase 1B (PTP1B)- an ubiquitously expressed non-receptor tyrosine phosphatase. PTP1B negatively regulates signalling pathways controlling metabolic homeostasis, cell proliferation and immunity (such as leptin and insulin receptor signalling), making PTP1B an interesting target for type 2 diabetes mellitus (T2DM) and obesity treatment. PTP1B also has important leptin-independent metabolic effects, playing a critical role in the regulation of inflammation, cell proliferation, differentiation and invasion. Therefore PTP1B is also interesting as a therapeutic target for inflammatory and autoimmune diseases and cancer.-For application data please see: Figure 2 supplement 1C.</p>

<p>Autocamtide-2-related inhibitory peptide is a calmodulin-dependent protein kinase II (CaMKII) inhibitor.CAMK represents a class of Ca2+/calmodulin-dependent protein kinase enzymes. CAMKs are activated by increases in the concentration of intracellular calcium ions (Ca2+) and transfers phosphates from ATP to defined serine or threonine residues in other proteins. Activated CAMK is involved in the phosphorylation of transcription factors and therefore, in the regulation of expression of responding genes.</p>

<p>Amino acids 359-409 of human glycogen synthase kinase 3 β (GSKβ), a multifunctional serine/threonine kinase widely expressed in most mammalian cells. GSKβ is highly active under basal conditions and acts downstream of phosphoinositide 3-kinase (PI3K) signalling. PI3K activation results in Akt phosphorylation and the subsequent phosphorylation of GSKβ at serine-9 and its inactivation. GSKβ in turn activates the production of pro-inflammatory cytokines including IL-1β, IL-6, IL-12, IL-17, TNFalpha and IFNγ, and supresses the production of IL-10, IL-1Ra, and IFNβ by immune cells. Under resting conditions, GSKβ is constitutively active due to tyrosine-216 phosphorylation, and it phosphorylates and inhibits a diverse group of pro-oncogenic substrates, such as: β-catenin- cyclin D1- c-Jun- c-Myc and CREB. GSKβ is also involved in Wnt signalling pathways.Aberrant expression of GSKβ has been shown to promote cell growth in some cancers and to suppress it in others. GSKβ inhibition leads to the accumulation of β-catenin in the nucleus, enhancing the progression of many cancers. However the inhibition of GSKβ also induces apoptosis in various types of cancers, such as pancreatic, colorectal and bladder cancer. Inhibition of GSKβ can also have neuroprotective effects on dopaminergic neurons such as in Parkinson's disease.</p>

<p>Phosphorylated EGFR peptide substrate.</p>

<p>Amino acids 487-496 of Poly(ADP-ribose) polymerase 1 (PARP1). PARP1 is a nuclear DNA repair enzyme that binds to DNA when damage is detected. PARP1 coordinates double and single strand break repair by first cleaving NAD+ into nicotinamide and ADP-ribose, and then synthesising poly-(ADP-ribose) (PAR) chains from ADP-ribose on target proteins (PARylation). PARylation of histone proteins mediates relaxation of the chromatin and recruitment of DNA-break repair enzymes.PARP1 can also act as a transcriptional co-activator, modulating the expression of itself and many other genes by direct binding to or PARylation of enhancers and promoters. PARP1 is also involved in maintaining mtDNA.PARP1 belongs to the PARP family which has 7 known and 10 putative members. PARP1 accounts for &gt;85% of the PARP activity in cellular systems.</p>

<p>Cell permeable peptide which is able to activate phosphoinositide 3- kinase, for which it binds with high affinity to the p85 subunit. 740 Y-P also has mitogenic activity as it is able to induce mitosis in muscle cells, and promotes cell survival in neurones. PI 3- kinase's are a family of enzymes involved in many cellular pathways including cell proliferation, growth, differentiation, survival, motility, and intracellular trafficking. PI 3 Kinases are therefore also involved in many cancers.</p>

<p>LRRKtide (also called moesin) is a peptide substrate for leucine-rich repeat kinase 2 (LRRK2). The sequence of LRRKtide has been derived from the ERM proteins: Ezrin (amino acids 561-573), radixin (amino acids 558-570) and moesin (amino acids 539-553). These proteins influence cytoskeletal dynamics by anchoring the cytoskeleton to the plasma membrane. LRRK2 phosphorylates LRRKtide at its Thr558 site.LRRK2 is a large, ubiquitous protein of unknown function. LRRK2 has GTPase and kinase activity, and is located in multiple areas of the cell where it is found associated with intracellular membranes and vesicular structures. Its multiple cellular locations suggest that LRRK2 may be involved in several cellular pathways. LRRK2 is also found in most organs and mutations in LRRK2 have been identified in Parkinson's disease.This peptides has an amidated C-terminal end.</p>

<p>AMARA peptide is a fragment containing the phosphorylation site for AMP activated protein kinase (AMPK) and is a substrate for all AMPK subfamily kinases. As such it is used to measure AMPK related kinase activity.</p>

<p>MGMT, known as O6-methylguanine-DNA methyltransferase, is a DNA repair enzyme that plays an important role in chemoresistance to alkylating agents. MGMT repairs the toxic DNA O6-Methylguanine lesion caused by Temozolomide (TMZ), an oral alkylating agent used for the treatment of glioblastoma. MGMT repairs damaged guanine nucleotides by transferring the methyl at O6 site of guanine to its cysteine residues, thus avoiding gene mutation, cell death and tumorigenesis. The expression of MGMT gene is mainly regulated by epigenetic modification. Loss of MGMT expression is due to methylation of the CpG island of MGMT promoter.</p>

<p>This peptide is phosphorylated by Janus kinase 1 (JAK1) and is an ideal substrate for use in kinase assays. The JAK family of kinases is essential for the signalling of a host of immune modulators in tumour, stromal, and immune cells where they are highly expressed. JAK family proteins mediate the signalling of the interferon (IFN), IL-6, and IL-2 families of cytokines.JAK kinases are associated with cytokine receptors. Cytokine binding to these receptors results in activation of JAK kinases and receptor phosphorylation. Phosphorylated cytokine receptors recruit STAT proteins, which are then phosphorylated by the activated JAK kinases. Phosphorylated STAT proteins form homo- and hetero-dimers that translocate into the nucleus and function as transcription factors.This JAK1 substrate peptide contains an N-terminal glycine-residue.</p>

<p>During extraction of lecithin from egg yolk, peptide by-products can be isolated and purified by gel filtration. Within the by-products this has led to the discovery of biologically active value-added products. The egg yolk gel filtration (EFGF) fractions were analysed for their antioxidant and angiotensin converting enzyme (ACE) inhibitory activities. EYGF-33 predominantly contained 3 peptides - KLSDW, YPSPV, and MPVHTDAD). KLSDW in EYGF-33 was found to have strong antioxidant activity linked to the presence of the tryptophan residue. KLSDW had nearly comparable activity to the synthetic antioxidant BHA. KLSDW did not show any notable angiotensin converting enzyme (ACE) inhibitory activity.</p>

<p>Autocamtide-3-related inhibitory peptide is a calmodulin-dependent protein kinase II (CaMKII) inhibitor. AC3-I is derived from Autocamtide-3, a substrate for CaMKII, with the Thr-9 phosphorylation site substituted with Ala.CAMK represents a class of Ca2+/calmodulin-dependent protein kinase enzymes. CAMKs are activated by increases in the concentration of intracellular calcium ions (Ca2+) and transfers phosphates from ATP to defined serine or threonine residues in other proteins. Activated CAMK is involved in the phosphorylation of transcription factors and therefore, in the regulation of expression of responding genes.</p>