| Description | Product InfoAssays employing crude extracts for topo II activity based upon relaxation of supercoiled DNA can be complicated due to the presence of topo I in partially purified fractions. Additional complications arise with contaminating nuclease activity (due to Mg++) which degrade or nick the Product InfoAssays employing crude extracts for topo II activity based upon relaxation of supercoiled DNA can be complicated due to the presence of topo I in partially purified fractions. Additional complications arise with contaminating nuclease activity (due to Mg++) which degrade or nick the supercoiled substrate. These problems can be avoided by using a catenated DNA substrate prepared from the kinetoplast of the insect trypanosome Crithidia fasciculata. Kinetoplast DNA (kDNA) is an aggregate of interlocked DNA minicircles (mostly 2.5 kb) that form extremely large networks of high molecular weight. As a result, these networks fail to enter an agarose gel. Upon incubation with topo II, which engages DNA in a double stranded breaking and reunion cycle, minicircular DNAs are effectively released (decatenated). The decatenated minicircles move rapidly into the gel owing to their small size. This reaction will not occur with topoisomerase I. The products of the reaction can vary as follows:Quality Control Tests:For catenated KDNA substrate, at least 90% of the DNA will be retained in the well of a 1% agarose gel.Decatenation of each batch of Kinetoplast DNA is tested with purified topoisomerase II.Storage Buffer:kDNA is stored in 10 mM Tris-Cl (pH 7.5), and 1 mM EDTA at the concentration specified with the product.DescriptionkDNA is the ideal substrate for topoisomerase II assays because it is specific for type II reaction mechanisms. Researchers can even assay for a type II enzyme in the presence of large excess of topoisomerase I. Thus, kDNA works well to quantify type II activity in crude cell extracts, which are frequently overloaded with topoisomerase I. The kDNA substrate works exceptionally well with human Top 2a and b as well as prokaryotic enzymes, such as DNA gyrase or topoisomerase IV. Shipping&storagekDNA should be stored at 4°C; however, long term storage at -20°C is acceptable. The DNA is usually shipped at ambient temperature... Read More | Inquire | Purity: >90%, by SDS-PAGE visualized with Coomassie® Blue Staining.Description：CNN1 is a member of the calponin family. CNN1 is a thin filament-associated protein which is involved in the regulation and modulation of smooth muscle contraction. CNN1 is able to bind to actin, calmodulinPurity: >90%, by SDS-PAGE visualized with Coomassie® Blue Staining.Description：CNN1 is a member of the calponin family. CNN1 is a thin filament-associated protein which is involved in the regulation and modulation of smooth muscle contraction. CNN1 is able to bind to actin, calmodulin, troponin C and tropomyosin. Prevention of actomyosin Mg-ATPase activity is a result of interaction between calponin and actin... Read More | Purity:>95%, by SDS-PAGE visualized with Coomassie® Blue Staining.Description：CD200 R1, also known as OX-2 receptor, is a 90 kDa transmembrane protein in the immunoglobulin superfamily and is important in the regulation of myeloid cell activity. The human CD200 R1 cDNA encodes a 325 Purity:>95%, by SDS-PAGE visualized with Coomassie® Blue Staining.Description：CD200 R1, also known as OX-2 receptor, is a 90 kDa transmembrane protein in the immunoglobulin superfamily and is important in the regulation of myeloid cell activity. The human CD200 R1 cDNA encodes a 325 amino acid (aa) precursor that includes a 28 aa signal sequence, a 215 aa extracellular domain (ECD), a 21 aa transmembrane segment, and a 61 aa cytoplasmic domain. The ECD is composed of one Ig-like V-type domain and one Ig-like C2-type domain. Within the ECD, human CD200 R1 shares 56% aa sequence identity with both mouse and rat CD200 R1. Alternate splicing of the human CD200 R1 mRNA generates four isoforms, two of which are truncated in the Ig-C2 domain and are likely secreted. In human, a separate CD200 RL gene encodes a protein that shares 81% ECD aa identity with CD200 R1. In mouse, at least four genes for CD200 R1-like molecules have been described. CD200 R1 expression is restricted primarily to mast cells, basophils, macrophages, and dendritic cells, while its ligand, CD200, is widely distributed. Disruption of this receptor-ligand system by knockout of the CD200 gene in mice leads to increased macrophage number and activation and predisposition to autoimmune disorders. Association of CD200 with CD200 R1 takes place between their respective N-terminal Ig-like domains. The capacity of CD200 R1-like molecules to interact with CD200 is controversial. CD200 R1 propagates inhibitory signals despite lacking a cytoplasmic ITIM (immunoreceptor tyrosine-based inhibitory motif). CD200 R1-like molecules, in contrast, are potentially activating receptors by means of their association with DAP12. CD200R1 signaling inhibits the expression of proinflammatory molecules including TNFs, IFNs, and inducible nitric oxide synthase in response to selected stimuli, which implicate that CD200/CD200R1 inhibitory signaling pathway plays a prominent role in limiting inflammation in a wide range of inflammatory diseases. Furthermore, the CD200/CD200R inhibitory signaling constitutes one of the most suitable endogenous immunoregulatory molecule candidate to restore the immune suppressive status of the CNS altered in chronic neuroinflammatory situations... Read More | Purity:>90%, by SDS-PAGE visualized with Coomassie® Blue Staining.Description：SOD2 is part of the iron/manganese superoxide dismutase family. It encodes a mitochondrial protein that forms a homotetramer and binds one manganese ion per subunit. SOD2 binds to the superoxide byproducts Purity:>90%, by SDS-PAGE visualized with Coomassie® Blue Staining.Description：SOD2 is part of the iron/manganese superoxide dismutase family. It encodes a mitochondrial protein that forms a homotetramer and binds one manganese ion per subunit. SOD2 binds to the superoxide byproducts of oxidative phosphorylation and converts them to hydrogen peroxide and diatomic oxygen. Mutations in SOD2 gene have been associated with idiopathic cardiomyopathy (IDC), premature aging, sporadic motor neuron disease, and cancer. SOD2 destroys radicals which are usually produced within the cells and which are toxic to biological systems... Read More |